I paid $10 for mine and have used it a few times. A senior pass is the same as senior pricing at some movies and restaurants. I think it is an effort to give back a little to a generation who has paid into many programs over the years.
The new administration, yes this one, upped the fee from $10 to $80 and I agree it still is a bargain if you use it. We are heading toward a place where the wealthy can afford it so the rest of us will be staying home. It used to be camping and seeing the national parks was something everyone could do. Tents are being replaced by motor homes just like housing tracts are being replaced by gated communities. I suppose when you run a trillion dollar dept you have to look for places to cut back. Setting up a fair system of taxation is pretty tough to do, no doubt, but squeezing the little guy has always been easy.