I get dedicated race vehicles but it just seems that if it's called Production, it seems like it should be useable on the street still. Then again Pro Stock and NASCAR both have Stock in the names, but what is stock about either of them?
I'd say up until about 10 years ago, it was still a viable option. When cages became required, that was pretty much the end of the line.
Personally, I think it's a shame, because I could think of nothing cooler than driving a car to an event, racing it, and then driving it home.
Realistically, here's the issue - you have to account for the fastest speeds possible.
SCTA-BNI does a great job of keeping their events safe, but the nature of the race course is such that if something lets go, one could be literally miles away from help.
Drag racing - 1/4 mile and shut-down, ambulance and tow truck - 30 seconds.
NASCAR - four corners to slow you up, ambulance and tow truck - 30 seconds.
A chute lets go at Bonneville, and you could be out of cell phone range before the help could even radio an ambulance.