Just want to clarify this.
Manchester United and Liverpool aren't in debt because they can't afford their players wages. The debt on both clubs comes from the way in which their current owners bought them. In fact, you could say that both clubs are operating with a major handicap in comparison to others as a result as we have even less money to spend on wages and transfers than we should have because our owners are using our profits to pay the interest on debts which we should never have had.
It's not like Leeds who went out and spent out more money than they could afford. Nor Portsmouth who did the same. Take off the debt repayments for our owners' mortgages and Manchester United and Liverpool make decent profits every year.
Chelsea have been bankrolled by a ludicrously rich man, which is fair enough. Manchester City are the same. Arsenal balance their books by cutting down on transfer spending while paying exceptionally high wages for the players they bring in. A wage cap wouldn't help the smaller clubs in England compete unless it was put at such a low level that European football would not be able to hold onto players in the worldwide market (the North American leagues and the Russian leagues, not to mention the Asian leagues would suddenly become very attractive again).