Rewriting of history there. The top four is more difficult for us now than it was then.
Depends what way you look at it. Arsenal were the invincibles, United had Ferguson, Chelsea under Ranieri were weaker but Liverpool had their treble winning side. Chelsea aside are any of these teams better now? They then all improved drastically (Arsenal aside) between 04-2010 with Mourinho shaping Chelsea, United getting Rooney Ronaldo Tevez, and Rafael making Liverpool a strong side with Alonso Mascherano and Torres. Virtually impossible to get in.
We missed the boat in those few years of transition when AVB messed up at Chelsea, City hadn't quite got become a superpower, and then even when Ferguson retired. After all those years of being 'best of the rest' when a team did actually drop out we didn't have our stuff together! Tottenham had Gareth Bale at just the right time whereas had we had Rooney at that point those two years in the top 4 could have been us.
I think last season was a massive opportunity for top 4. Liverpool and United seemed to fall over themselves trying to get it. They had two of their worst premier league sides whilst we supposedly had a settled squad, we should have blown them away but we just didn't even turn up.
I fear you'll be right from now on as City Chelsea United and Arsenal will now lock down top 4 and we'll have to wait until another rock in the stream (one of them appointing a poor manager) for anther opportunity to appear. As long as Mourinho Wenger Pellegrini and Van Gaal are there though we can all kiss top 4 goodbye.