I should imagine the guys buying the high $$$ cars are getting historic plates. Here in Missouri they are pretty cheap ($15 additional) and are lifetime plates. There are restrictions on personal mileage per year, outside of "educational" uses (including car shows, displays etc) and a mileage log must be kept. You can also get personalized historic plates but they need to be renewed annually. All told, Missouri has something like near 200 plate variations. We've got hotrod, agricultural, truck, bus etc but no muscle car
But I can use a 1971 plate on our '71 R/T as long as the number doesn't conflict with the current numbering system
Here's some more information if anyone is interested.