It was Italian team's in the 90's, and nowadays it's the English teams plus Real Madrid. Blaming Spanish teams for the inflated transfer prices is ridiculous...Real Madrid is the only team in Spain that spends like crazy. True, over the past couple of seasons Barca started spending like crazy to keep up with Real (Villa being the only transfer that actually panned out), but they have 8 out of the starting XI from the youth academy, and historically speaking, aren't super heavy spenders considering they're the second biggest team in the country. Every other team in Spain is **** poor pretty much. Look at Valencia. If we compare the amount spent each transfer window per league, the Prem outspends La Liga by far. Real Madrid is the only big spending team, with Barca occassionally coming it to make a stupid transfer. The rest run on an extremely tight budget. True, if you look at the top 15 transfers of all time, it looks like Spain is dominating the transfer market, but that's just because Real Madrid has had their two phases of galacticos. Heck even during the non-galactico era they really weren't heavy spenders considering their stature.
The FFP will hopefully slow things down but that's not the only issue, there's a real lack of sustainability that could destroy these clubs. However, maybe they have become 'too big to fail.' Seems to be the trend these days.