I don't think that is the answer.
I know that sounds weird but let's think about this for a second. Why haven't any Sheiks, or Princes, or Oil Barons come into Serie A to buy any of these clubs?
We are talking about clubs with history, some with histories greater than the likes of Chelsea and PSG, when talking about Inter, and Milan for example. Clubs that had domestic, and more importantly, European success in their history, and were able to sustain it for a longer period of time.
A club like Roma for example, the #1 team in one of the most prestigious cities in the world.
Nary a sniff from the aforementioned billionaires?
Why is that? Well, from where I stand, what is there to invest in? Why spend all of that money, when with FFP breathing down your neck, you would have to end up paying it back and then some when the league, and consequently, the club you own, won't be able to generate enough revenue to keep up with your spending? Everything is antiquated, everything is backwards in the peninsula. So, if I'm one of those prospective owners with all that money, I would rather take a chance on a mid table team in the EPL or La Liga, and at least get good return on my investment.