Implying Manchester United don't have filthy rich owners.
Well they're in huge debt.
What i am saying is that clubs that are financially strong by building on success (Man U, Real, Barca, Bayern, Juve, ACM, Arsenal etc.) get alot of their income based on revenue from fans, merchandise, sponsorship etc. These teams are rich because they made their names on success, they didn't just come out of nowhere and suddenly start competing in the champions league if you know what i mean.
But yeah, the Glazers are rich as fuck, yet the entire club is in debt, kind of like Real. Bayern probably have the most succesful system by operating like your average company with stocks and without the ability to buy a majority stake.