I think the old car hobby will be slowly killed by the environmental folks. Well, you'll be able to HAVE an old car but it won't be allowed on the road without airbags, ABS, crash testing and all the other crap new cars have.
There will be special tracks where your car will be towed around like a bumper car because the engine spews too much pollution into the air.
And, as mentioned, cars from the current era will be "recycled" after the "Best Before" date.
Unless the "hobby" gets even more active in preventing this kind of legislation, we're doomed to using old cars as planters.
Besides, the old cars we enjoy are not the old cars future generations will enjoy...it's usually the cars you grew up with that hold the allure, so Accords and Civics are the ones that will be popular.