A lot of them retired early so they could get the lump sums before BK wiped it all away. They have plenty of years left in them if they decide they want to keep going. Health insurence premiums- especially for those with kids that aren't out of the house yet- are insanely high so a lot of them have more incentive to take the job for the insurence. Yes, overall it is a small amount of the overall retired airline population, but it is a higher amount than before due to the financial disasters at the majors currently.
Overall I'd say attrition isn't very high at the fractionals now that salaries are going up and there is less incentive to jump to the airlines. There are a lot of older pilots, but it is really up to them when they want to get out. I'd have to guess that a lot of guys are going to be flying well past 60 since their pensions have been destroyed by years of mismanagement at the airlines they gave the best years of their lives to. It's a very unfortunate situation they are in, but at least the fractionals offer them the opportunity to continue earning money in the best kind of office in the world- the cockpit.