I just have a TON of hair, so I can relate. the funny thing is my hair isn't super thick, I just have a lot of it.
But I've never once thought JFK had a toupe, just good hair. Those other guys you posted clearly have toupes though. JFK doesn't look like it at all. Plus, the fact that his whole family (brothers/kids) had a great hair, no balding makes me think it's genetic too.
Sorry, I still think it's real!!