LONDON • As China prepares to greet the Group of 20 leaders of the world's biggest economies for their yearly summit next week, nothing has been left to chance.

The G-20 agenda has been carefully scripted to include discussions on lofty ideals such as the promotion of an "innovative, invigorated, interconnected and inclusive world economy" as the Chinese hosts put it, rather than on boring little details such as the escalating territorial dispute and arms race in the South China Sea which, as Beijing sees it, is nobody's business.

Over 30 "action plans" for the world's future will be adopted. And hundreds of factories around Hangzhou, the city which hosts the summit on Sept 4 and 5, will close for the occasion, in a bid to ensure that world guests see nothing but blue skies and red carpets.

Yet no amount of clever summitry can disguise the fact that, although the G-20 is a useful framework for discussing global economic problems, it won't be the forum to remake global power relations in the way that those who initially conceived the institution intended. A similar failure afflicts the so-called Brics group of five major emerging national economies, which also generated huge reform aspirations, all of which have now turned to dust.

The result is that no united block of emerging economies is about to challenge the continued dominance which the US and Europe enjoy over global markets and institutions. But far from seeing this as a reason for rejoicing, Western leaders should view this outcome with anxiety, since the pent-up demand for change to a less Western-centric global power arrangement remains undiminished, and could well manifest itself in less manageable formats in the future.

STRANGE DISCONNECT

The debate about the rise of new emerging powers and the eclipse of the old Western world has dominated thinking in all Western capitals for the past two decades. Some Western leaders and foreign policy specialists argued that this shift in both global economic and political gravity could still work in favour of the old West by creating a new "Concert of Democracies", as academics grouped around the Princeton Project on National Security argued back in 2008.

Others, however, predicted a darker fate for the Western-dominated world, one in which the new, so-called Beijing Consensus, which supposedly relied on the exercise of naked power and national interest untamed by considerations of human rights or good governance, would triumph, erasing decades of Western-dominated norms.

Be that as it may, all sides in this debate accepted that the shift from West to East and from North to South was irreversible; in the words of a US National Intelligence Council report from 2004, "only an abrupt reversal of the process of globalisation or a major upheaval" could prevent this from happening. And there was a second argument on which most Western nations agreed: that instead of trying to halt this shift in the power balance, they should try to channel it in ways which will manage change and avoid disruption.

That, in a nutshell, was the thinking behind the G-20 idea: it was launched in 1999 by the G-7 club of wealthy nations as an explicit acknowledgment that their old charmed little circle could no longer continue as before and needed a broader forum of engagement with rising powers.

The G-20 was designed to be small but inclusive: the 19 countries plus representatives of the European Union which will be attending next week's summit in China account for two-thirds of the world's population, 75 per cent of world trade and around 85 per cent of gross world product, a far more substantial representation of global power than the United Nations' Security Council.

And there is no question that the G-20 did useful work, especially since 2008, when its heads of state and governments agreed to attend summits. The G-20 was critical in managing the global financial crisis largely by what it chose not to do: its leaders refused to bow to the temptation of protectionism, thereby easing the management of the crisis.

But the G-20 failed to become either the economic or the political "global steering committee" that it wished to be. For, paradoxically, it ended up mimicking the mistakes of past Western-dominated institutions. It failed to foresee the need to consult nations outside the G-20 about decisions which directly affected them, an error only partly corrected by the emergence of the Global Governance Group, an association of non-G-20 nations inspired and led by Singapore. It also failed to exercise broader transparency and accountability duties.

But the G-20's biggest failure comes in its strange disconnect from the broader reform agenda of international institutions. There have been no innovative ideas about the reform of organisations such as the United Nations. And even on financial institutions, the G-20's impact remains minimal: it promised to deliver an overhaul of the International Monetary Fund's quotas and voting powers by 2010, but only succeeded in doing so in 2012, and the changes are only coming into effect now, a seven-year cycle of labour for what are still very modest proposals.

And, apart from some generalities about promoting "development" or "gender equality", nothing much was done in other areas as well. At next week's summit, only three out of 20 leaders and only two of the central bank governors will be female; the rest - including all finance ministers without exception - will be middle-aged men in identical grey suits. Welcome to the new world, which somehow very much resembles the old one.

The disappointment of the G-20 is also mirrored by the decline of another organisation which was meant to change the world: the Brics, composed of Brazil, Russia, India, China and South Africa. The idea of Brics came from the creative mind of the chairman of the Goldman Sachs investment management and was always a bit of a nonsense. There was little in common between, say, Russia and India: the former is largely a commodity exporter with a declining, ageing population, while the latter is a commodity importer (but seldom from Russia) with a youthful and expanding population. Still, the myth that the Brics will take over world leadership proved intoxicating: in 2012, a weighty tome published by Oxford University Press claimed to have discovered that the Brics are already in a global "leadership position".

Brics leaders also played this up for what it was worth, pretending to act in unison.

But appearances can no longer hide realities. For in South Africa, Brazil and Russia, corruption and governance failures have proved catastrophic, destroying economies and governments; and while China's and India's economies are still growing, they are increasingly diverging in every respect. Meanwhile, global investors are fleeing: the cash taken out of the Brics more than unwinds all the inflows of capital since 2005. In global policy reform terms, the Brics' contribution has been precisely zero.

PRESSURE ON THE UNITED STATES

All this means that, for the foreseeable future, there is no substitute to the United States as the world's pre-eminent power. China's rise has rendered the US more, not less, important. The biggest pressure on the US today is coming from its allies and partners, all of whom want more American protection and support; the provision of US security guarantees is, to use the financial market's parlance, a "demand-led", rather than "supply-led", affair. And although the Europeans are paralysed by their internal problems, they also matter more than in the past, precisely because there are not many other serious players willing to take on responsibility for global problems.

The snag for Western governments is that, although their domination of international institutions now appears more enduring than initially expected, it cannot be maintained indefinitely; reforms to the world order and to global organisations are still required, although there is no agreement on what needs to be done and no framework for implementing these changes.

So, at least for the moment, everyone prefers to uphold the old, familiar cliches. Chinese ambassadors around the world have been instructed to place articles in newspapers of the countries to which they are accredited, all praising the upcoming summit's importance. Western leaders, meanwhile, claim to treat the summit in China as one of the highlights of the year.

And investors are voting with their feet. Goldman Sachs, which invented the Brics concept, has pulled the plug on the investment fund which tracked the economies of these countries.

It now claims to be seeking "a more diversified universe". No doubt, someone will invent an acronym for that, and predict that it is poised to take on the world.