I'm 59 and the hubby is 68, just to give you a perspective.
Most of the people we see in RV parks are older than the hubby and significantly older than me. Could be that younger people don't have the pensions but there is one geezer here that is living on his social security and darned happy! His coach is old and truck even older, but he gets to go fishing every day and jaw with his mates every night. I think almost anyone could afford that lifestyle.
There are people in every generation that go the instant gratification route, it is not just a "youngster" thing. We had neighbors who were about the hubby's age who had never saved a dime, always rented their home, and always drove a fancy new truck. Boy were they surprised when they found out how much SS would pay! They are still working and last time we talked all they could do was complain about how "lucky" we were.
I'm staying away from politics. There seem to be no company pensions any more but some can adjust to living on less and they are the ones traveling. Others have obligations that keep them off the road. Some can't travel unless they can have it all with them. The answer to why there are less snowbirds is as complex as the people it's about.