As mentioned elsewhere these comments stem from people who think that football began 20 years ago. Sky really push this notion by referring to historical records as The Premier League rather than the top flight. The coincidence of the Champions league exacerbates the problem.
United Aresenal and Chelsea were just fortunate in that they had good spells just as all this happened which concentrated all the power and money in the top clubs, which created this self-licking ice cream. Had it happened in a different era (70's) we may have seen domination from Leeds, Derby, City or Forest. Or Wolves and United in the 50's
Kaka was playing for Milan when he made his (alleged) comments but his ignorance is borne out of Italian football always being dominated by a few clubs. He'd probably accuse Torino of having no history.
But change might be on its way. The world dominance of EPL may be waning a little with the resurgence of Real Madrid, and one could make an argument that all 4 of the big 4 could be weaker next season -
United - lost Ronaldo and Tevez, Ferdinand injury prone, Scholes Giggs and Neville past it,
Liverpool - may lose both Alonso and Mascherano
Chelsea - will lose Carvalho and Deco, possibly Terry, others getting on a bit.
Arsenal - appear generally to be heading in the wrong direction
As soon as City break the mould it could be the slippery slope for one or two of these. And in 20 years time the history will start to look a bit different - or actually, the same as it ever was.