I don't think it could ever be easily enforced, similar to how you can't easily enforce a "ban" on drinking or guns. In rural areas where cops practically don't exist, you can get away with almost anything. My buddy in Arizona says he hasn't seen a cop drive down his street in over 10 years. So even if it ever is "banned" a long time from now, good luck trying to enforce it in super isolated towns, desert roads, and so on.
Nor do I think oil companies, aftermarket part companies, or performance part companies will sit back and watch their empires crumble before their eyes -- they'll lobby against it.
Anyway, I was at a classic car show today. It was mostly muscle cars and sports sedans. The leaded gas and old vinyl seats smell amazing. They also had a drag racing area, and quite a few cars surprised me with their performance capabilities. There was this Chevy Malibu Station Wagon which out-accelerated a Pontiac GTO, I know quite a few people were pissed when placing bets on the GTO.