With the exception of the moment you sell it, owning a professional sports team is a giant money sink. The obscenely rich do it for the attention and to rub it in the faces of all their friends. No matter how rich you are, you cannot own an NBA team unless an existing owner wants to sell or unless you pay off the existing owners to allow an expansion team.

Both attention and bragging rights increase the more a team wins. No owner wants to be in a position where they paid a lot to buy a team, have to pay a lot in team payroll, but still lose. If an owner is already heavily invested in a team and sees an opportunity to invest a little bit more for a lot more success, it makes sense to take it.