The bus driver who works overtime because it's available for him is not the same guy as the union rep who fights for absurd pay schemes that screw over the taxpayer, or the politician who agrees to the union demands because he wants their votes in the upcoming election.
Have you guys ever had a union, shift job?
ADDITION: Many union workers don't even like the unions they are a part of. The vast majority of those involved have little to no say in their representation, or at least think that's the case. They show up to work, get paid money, pay money in union dues, go home, put food on the table, and don't think about it. Don't believe that an average MBTA employee is any way responsible for the fact that his union is overpaying him, when that is simply not the case. Again, if you thought you were being overpaid, would you give your salary back to your boss rather than help your family? Of course not.
Heck, union workers have far less control over their salary than non-unionized employees. They can't negotiate pay. They have to operate under the strict rules of the union.
DOUBLE ADDITION: We clearly aren't going to agree. You blame overpaid MBTA employees. I do not. That's okay. We all think there is a problem. And the union rules have to be overhauled, or even removed.