But you can clearly see that there has been a consistent concentration at the top, because top teams just are better now. Ancelotti's Milan spend more time outside the top 3 in Italy than inside it. They won the CL twice, but they were certainly no all time great side, just like the Galacticos they were more name than game.
The 2000s has been an era where mid and top were not far apart. That's how Valencia, Leverkusen, Monaco, Porto appear in CL finals (and even the big teams like Bayern were not particularly impressive). Or that's how Greece can win an EC, in which the Czech Republic was the only good team. Or that's how the worst Germany squad in decades reached the WC final vs USA, Paraguay and semifinalist South Korea and that wasn't even deserved, just us being outplayed and getting saved by Kahn until he fucked up in the final. The early to mid 2000s wasn't a football wonderland, it was a confusing time with great individuals but troubled collectives.
Yes, you still had "supersquads" in the 2000s also, but for every squad like Milan or the Galacticos you had 5 Bayerns, and Liverpools that had above-average squads but would still beat them.
Now back to the present? Where are the upsets? Big teams are too consistent and too big. They have mopped up everything below them, when a player at Dortmund, Ajax or Benfica does well, guess what happens: He plays at City next year. Or at Bayern. Or Madrid. Or Liverpool. And CL finals happen between the biggest teams now. Tottenham was really the only exception in that whole decade.