As sad as it sounds they can. They just don't have to admit it is all. They always try to get the older ones out one way or another. Some of those elderly ones in their upper 60's-80's are extremely costly on the medical side for the company. Higher cost to them than just a simple 100K buyout offer.
I can count on two hands how many guys are getting rather large medical issues taken care of prior to retirement. Extremely costly to the company to keep those types. Now don't get me wrong here, a lot of them are not costing the company anything in medical, but the few that are outweigh the ones that are not as they are retired way before the ones getting all the medical issues out of the way.
If SWA offered another buyout with what UAL offered (up to 100K) they would get a lot of takers this time around.