You have to think about it this way, how often do players have a great first season at a new club? Almost never and thats because they have to adjust to a whole load of things, one being playing with guys you haven't been playing with regularly. A lot of soccer is about knowing your team mate and what he is going to do, i mean you have to be able to predict where the guy is going to run and where the dude playing the ball is going to play it.
In the past the teams outside the top 10 were terrible usually, and you would rarely have an upset, but now those teams have gotten better. With the relaxation of EU working laws it has become much easier for players for Serbia, Sloveina and the then minnows of europe to find their way into the big time league of england, germany, spain and italy.
Also the world has become more confident in African players after the success of Radebe (remember he captained an English champions league team) and the like and thus they get to gain experience in the top leagues. The South American leagues have become more competitive as well, with players actually opting to move back and play in South America (Riquleme, Veron and co.)
And the final point i have is coaches are no longer scared to do the Italian thing and park the bus because the Italians have proved it works. You have to be very good to break down these defenses and not being able to link up with your fellow country men becuase you haven't had enough time together on the training ground makes all the difference. They dont care about attractive football anymore, winning is winning. In the past a single defensive midfielder was an option, now 1 is must and some coaches are even playing 2. Korea lost 2 - 1 to Brazil, but played with 2 rows of back 4's.
. Every time they do that I say, there's a few million pounds investment right there in the stands 