The Glazers are in the recapitalisation business, bibble. If Man U hadn't been sitting on such wealth ; which it wouldn't have been if run like a normal company; they wouldn't have been able to buy it using borrowed money and then use the company's money to pay the lenders,.Nothing wrong or illegal in that, but it's nothing to do with being interested in football.
Winning the championship, year on year, doesn't matter much to them. While Man U has its following worldwide, already well established long before they arrived, it has a big market value. Their problem is waiting for the world economy to pick up enough so they can clear out to some buyer. It looks as though the number of sheikhs who want to buy a club has been met, so they have to look elsewhere.