Under FFP rules, no club will be allowed to pay out in salaries more than it earns. This won't include investments, of course, which will allow for improvements in infrastructure and revenue gathering streams, but it means that the fat cat clubs of the Premier League will come back towards the more financially prudent slimline models and make the PL more competitive, which it badly needs to be. The investment of a £15M Academy infrastructure is also cheaper than buying in half a dozen international quality players. Granted, you can't guarantee the time, the number of players, or the quality you'd get out of it, but those that didn't measure up would be sold on. Within a few years the quality and numbers would rise significantly, and eventually effectively pay its own way.
Although I doubt if Cortese even allows for thoughts of relegation, a simple clause in contracts would only be required to keep most things on an even keel. Clubs that fall into the trap of doing well in their first season, only to be relegated in their second, just have themselves to blame. They haven't made it and neither do they have a divine right to stay there. Since the real money is to be made at the very top of the PL, it behoves clubs to make sure they keep as close to that position as possible. That way you avoid relegation as well.
I'm a bit surprised by a few of the answers, so far. Obviously a few need to start a thread on US politics to satisfy themselves. Also, by those who are keeping to the subject [my thanks], there's been a lot of getting bogged down in the detail. You're not football managers, you're the helmsman. You decide where the club goes and how far you intend to take it. Anything else is delegated to others. Where's the ambition..?
The Financial Fair Play rules (as they stand) say that a club can't spend more than 100% of turnover on wages. No sensible businessman who values his money is going to go above that and very few teams do. It's only the clubs run as vanity projects like Man City that break this rule and they can probably get around it with some creative accounting. The ruling is just there to make UEFA think it's doing something, but UEFA can't do any more until the clubs take it upon themselves to reform, because that's how capitalism works.