LONDON • Lucrative television deals, owners and investors with seemingly bottomless pockets, financial fair play not necessarily being fair - these are numerous reasons for the expeditious rise in Premier League transfer fees.
Forty-five days remain in the transfer window and already last year's record summer total of £822.5 million (S$1.47 billion) appears set to be broken, and it may reach £1 billion if mooted moves such as Paul Pogba to Manchester United (around £100 million) go through.
What this ongoing window has been most notable for so far, however, is the arrival of a new barometer: the £30 million fee.
There were five £30 million-plus transfers last summer but this year, an amount unheard of a decade and a half ago for the world's best has become the norm for good - but arguably not exceptional - players.
Sadio Mane, Granit Xhaka, Eric Bailly, Michy Batshuayi and N'Golo Kante have moved for around £30 million each - but what would that amount have bought in the past?
FIFTEEN YEARS AGO
Juan Sebastian Veron became the Premier League's record signing in 2001 when he joined United from Lazio for £28.1 million, a fee still some way off the world record €75 million (S$111.8 million) Real Madrid paid Juventus for Zinedine Zidane that same year.
Twelve months later, Rio Ferdinand moved to Old Trafford from Leeds for £29.1 million but with add-ons and fees bringing the total to around £34 million, he again broke the British record and became the world's most expensive defender for a second time.
Previously, Lilian Thuram's move to Juventus had usurped the £18 million Leeds spent on bringing Ferdinand to Elland Road from West Ham.
TEN YEARS AGO
In a list of the top 50 transfers of all time, what is perhaps most noticeable - apart from the majority at the top being quite recent - is a gap between 2002 and 2006 where no record fees were set.
However, in 2006, Andriy Shevchenko joined Chelsea for £30.8 million and two years later the nouveau riche Manchester City muscled in with the acquisition of Robinho from Real for £32.5 million.
City's signing of Carlos Tevez 12 months later for £47.5 million took the spending of English clubs to a new level.
FIVE YEARS AGO
Even in 2011, fees above £30 million were not common and were reserved, with only a couple of exceptions, for the world's best players.
Cesc Fabregas' return to Barcelona earned Arsenal £38 million, while City spent the same amount on Sergio Aguero.
An English record had been set with Fernando Torres' £50 million move from Liverpool to Chelsea on the final day of the winter window, although Andy Carroll moved from Newcastle to Anfield for £35 million on the same day.
Liverpool, it should be noted, had also signed Luis Suarez on the same day for £22.8 million, a price that in hindsight was a bargain.
Transfer spending has steadily risen in recent years - Arsenal paying big money for Mesut Ozil in 2013 and Alexis Sanchez in 2014, while Chelsea offloaded Juan Mata and David Luiz in the winter and summer transfer windows respectively two years ago.
And the five moves costing more than £30 million belonged to three of the elite.
City spent a combined £134 million on Nicolas Otamendi, Raheem Sterling and Kevin de Bruyne, and Anthony Martial became the world's most expensive teenager when he joined United from Monaco for £36 million.
The most interesting of all, however, is Christian Benteke, considering Liverpool's desire to offload him and Crystal Palace's willingness to spend almost the same amount to buy the striker this summer.
His £32.5 million transfer from Aston Villa to Anfield was an eyebrow-raising fee for a player most notable for saving a team from relegation.