The objective was to prevent collapse. The return was just a bonus. It would have been the height of irresponsibility to lose time while negotiating a bigger vig for the tax payers as the financial system burns to the ground. A 25% return in two years is nothing to complain about and if the return had been say 50% it would still be almost completely unnoticeable to the tax payers.

That doesn't mean it was right to not change the source of the problem after the crisis, but that's a whole other debate.