The 'Big Six' has become such well established term in Premier League parlance that it is never questioned: but it should be now.
To back up the evidence of the entirety of last season, the start of this campaign confirms that we are now looking at a Big Two of Manchester City and Liverpool, who go head-to-head at Anfield on Sunday.
Twenty-five points separated Liverpool in second place from Chelsea in third last season. That is a massive gulf even by a conservative estimation.
Jurgen Klopp (left) and Pep Guardiola (right) go head-to-head at Anfield on Sunday
It is true that reigning champions Manchester City, who finished one point clear of Liverpool on 98 last season, are currently just two clear of Leicester and Chelsea, but few would bet against that gap widening significantly as they strain to keep up with Jurgen Klopp's pace-setters six points ahead.
The Big Six has evolved into being over the last decade. In the last 10 seasons, on just six occasions have teams other than City, Liverpool, Manchester United, Chelsea, Arsenal and Tottenham finished in the top six places in the Premier League.
The most famous of those, of course, is Leicester's miracle title win in 2015-16. Along with them Southampton (2015-16), Everton (2013-14 and 2012-13), Newcastle (2011-12) and Aston Villa (2009-10) are the only teams to have shaken up the establishment.
However, not only are Leicester set to gatecrash the top six again, but we are once again set for a two-horse title race, with United, Tottenham and Arsenal all well off the pace set by the Big Two.
Here, in chronological order, are the key factors as to how the order has shifted...MANCHESTER CITY'S SHEIK TAKEOVER
City were the final piece in the jigsaw of the Big Six forming when they finished inside the top six for the first time since 1992 in 2010.
There can be little debate as to the reason for that. Billionaire Sheik Mansour took over the club in 2008 and immediately set about a project of heavy investment which has propelled City into the Premier League and Europe's elite.
They have won the title four times, including the last two, and they have the Sheik to thank for it.
By buying their way into the Premier League's top table, they have also knocked their rivals off their perches and have been the most dominant domestic team since their first title in 2012.
There is no sign of that dominance dissipating while Pep Guardiola is at the helm.
Sheik Mansour (centre) took over Manchester City in 2008 and has delivered four titles so far
When Arsenal's Invincibles won the Premier League in 2004 without losing a match, no one would have thought we'd be sitting here 15 years later without them having added another title. But here we are.
Arsenal, in fact, have not even come close to winning the title since then. The two seasons they have finished second since, in 2005 and 2016, they finished a distant 12 and 10 points off the champions.
Arsene Wenger's credit in the bank for winning three titles from 1998 to 2004 meant that the club refused to sack him despite them entering a terminal decline that they are still showing no signs of snapping out of.
Having been part of a two-club dominance of English football with United, Arsenal went through the motions under Wenger for over a decade and have now failed to finish in the top four in each of the last three seasons.
Arsenal went into decline under Arsene Wenger and have still not snapped out of it
This is arguably the single most deciding factor in a new order of Manchester City and Liverpool being established.
Again, the bare facts spell it out best. Manchester United won the Premier League in 13 of 21 seasons under Sir Alex Ferguson. Since he retired in 2013, they have won none of the last six, with that record certain to extend to seven with Ole Gunnar Solskjaer's team already 18 points behind Liverpool after just 11 matches.
Love him or loathe him, Fergie had an iron grip on the Premier League. United players played above themselves for him and opposition teams would wilt in his presence. For those of us who grew up watching United win everything, it is clear the aura that United had was largely the aura of Ferguson.
With him gone the rug has been pulled out from under United, and City and Liverpool have stepped into the breach.
Sir Alex Ferguson won the Premier League for a 13th time in his final season in 2012-13