Well, In actuality as I'm sure you know chapter 11 is not really bankruptcy, I believe that is chapter 7.
Withe 1.8 Billion dollars in outstanding debt and 220 million in annual interest payments, there wasn't much of a choice.
Some of the bonds were paying as much as 12+ percent.
I can get a better dividend keeping my money in a pickle jar than in a bank these days so getting 12+ percent on your money is virtually unheard of.

What I think was the final nail in the coffin was the opening of the Borgata.
Even with a modest loss in revenue and perhaps only a temporary one due to the new kid on the block I believe it was the straw that broke the Donald's back

Speaking of Donald's back, I'm sure he will be.
Like a boomerang he always returns.