The '59 and '60 Chevys WERE popular - they were also dangerous to drive on the highway. Those fins provided lift - enough to reduce rear wheel traction at high speed. Highway patrols bought fleets of these cars, then rapidly sold them once the "bad car" reports began arriving.
My dad bought our family a brand new '60 Impala. Mom drove it. She rarely drove on highways, so she thought the car was wonderful. Then we took it on a cross-country vacation (with dad at the wheel). All opinions about that car changed, and not for the better.
https://www.jalopyjournal.com/forum/threads/1959-chevy-rear-end-lift-at-speed.984050/