There are still tons of cars from the 90's and early 2000's on the road (in particular the '01 Camry), it'll be at least 20-30 years and anyone with a new car being limited is just going to be harassed for driving way too slow relative to traffic.
And even once this is over, I think it's pretty often the speed limits and not the people driving over them that are in the wrong. I don't think slowing everyone down is a useful goal unless we adjust the limits up first.
