Thing is, big players did not want yugoslavia because it was a really decent socialist country. They found people who were made rich in the process and were willing to start spreading the hate. Fans were manipulated by some leaders who also ended up full of money at the end of it all. And all the countries ended up poorer and in the worst state than before and still not recovered.
Sport also suffered, because than you had 5-6 big clubs and now everyone ended up with 1 derby and a bunch or blah games.