Domestic Titles
Real Madrid: 30
Juventus: 27 (+2?)
Barcelona: 18
Liverpool: 18
AC Milan: 17
Manchester United: 16
Internazionale: 15
Arsenal: 13
Everton: 9
Athletico Madrid: 9
Genoa: 9
there's only been 9 different winners of la liga in its history, 17 in serie A, we've had 23. If you look at leagues in Belgium, Netherlands, Scotland, Austria, Sweden, Denmark, Turkey, Greece, I'm sure they are dominated by even less clubs.
We are merely coming into line with other nations
imo. Other nations had less clubs than England and as such the bigger clubs had more fans, whereas in the 'olden days', if you couldn't get into Old Trafford you'd go to Maine Road etc, all the stadiums were close in size, and as such all clubs had around the same income, and players would stick with clubs because they couldn't always go elsewhere for more money. This didn't happen in Spain, Italy etc where the better players have generally always moved to the bigger clubs. With TV, and expanding stadiums the bigger clubs' fanbases can expand beyond their previous limits, and more importantly their revenues. Thus leading to a higher concentration ratio of champions.