Agreed on the too much insurance & registration costs, and not enough time to drive them all regularly. But, when the day is right and you really want to drive a particular car, it's there. (So long as the battery is charged.)
A former goal was to own one car from each year of the muscle car era. I got pretty close...I had more than one car for each year of 1960, 61, 64, 66, 67, 68, 69 and 70, but I never owned a 1963 or '65.
Also had a sweet black '57 Thunderbird E-model, with factory dual fours and a three-speed stick.
It's very interesting to see/feel the almost-yearly improvements in power, speed and overall engineering of all those cars I had. Fun to experience for a guy like me who was a kid way back then and longed to be able to drive. By the time I got my license in the mid '70s the new cars had turned to crap. I've owned '60s performance cars since my very first car at age 16.
And, yes, I'm an old guy. But I still drive like I'm a young guy, and will race just about anything that challenges me.