I've owned a long list of what are now defined as "collector cars"...I'm soon 63 years old. While of course I wish I had some or all of them today, I was never "wealthy" and each one got sold or traded off for the next over the years....
At the top of my "wish I coulda kept them" list: 1970 Road Runner, 2-speed, 440-6 pack. 1957 Bel Air with 1967 Corvette 327-365, 4 speed. 1963 Cadlillac El Dorado convertible., 1972 Pantera, numerous 66-77 Broncos
On the flip side, I recently came across a 1927 Dodge Brothers "Fast Four" coupe up for auction that was identical in every respect to the one I restored back in the late 70s/early 80s. It sold for only $6500!...mine was valued at a lot more than that over 40 years ago. Values change as tastes and collector "wants" change over time.