There are many things that could be done:
1. B-spec
2. Login bonus
3. Seasonals with high payouts like in GT5/6
4. Increase Sport mode winnings
5. Allow us to sell gift cars
6. All of the above?
All while still keeping the 20 million mythic price that PD seems to associate with a bunch of pixels arranged to look like an actual priceless car. But nope! Doing the same repetitive easy races again and again is the true mark of an elite player that will grant you access to these artificially inflated cars. /sarcasm
For the record, I don't think the actual car itself is worth 40 million (or whatever a 250 GTO goes for in an auction these days). I'd just laser scan every inch of the original, commission my own 250 GTO built to spec with modern more reliable components and drive the living daylights out of it. Crash it? No problemo, just build another one. Enjoy the car for what it's made for, instead of auction investment pieces.