The ones up for sale in a general classifieds site are likely to be the higher-used ones. Many private collected Ferraris are driven under 100 miles per year, but won’t show up in general classifieds. (If they change hands, it’s more likely via word of mouth or marque-specific forums like f-chat.)
This seems like an easy fix if they're not actually being driven, just don't make these supercars street legal. Have the exemption be "if you're driving the car on a racetrack then it can be ICE."
The f-chat listings are significantly lower miles/year: https://www.ferrarichat.com/forum/forums/cars.303/