Greed pure and simple. We all got into the airlines knowing that at 60 we would be retiring. I shouldn't have to pay for poor planning by someone else.
The other thing I don't think people realize is that we as pilots won't have control over what the requirements would be to fly past 60. The FAA could say, "Fine, you want to fly past 60. Then you're going to have to submit to all of these extra tests at your own expense(ie. there are only two locations in the country that can conduct them and it'll cost $1000) every 6 mo. to keep you first class medical."