Right now, interest in baseball is great enough that no team is remotely in danger of going out of business. If a team were drawing under 10,000 a game or so, there would be a problem. But in today's game, the sport is competitive enough to survive just fine. Name any team that has been terrible the last 5 years, and I can show you the clear path of ineptitude that led them there, not economics.
The point is that no team has done it. The Yankees can fall. They have ALOT of money tied into some players. Jeter, Giambi both make $20 mil. They'll age, and they'll still be paid. There may come a point where the Yankees fail to succeed, and then the revenue dries up.