The people spending big money have "museums" so they can write off part of the price as a capital investment, some might be 501K foundations where they can claim the car as a donation on their personal taxes and the foundation doesn't have to pay any tax on it.

These guys are operating at a level where retaining a sharp tax lawyer is part of the deal (and probably deductible).

The next level down are dealers who count on the constant price inflation for their profit.

Guys who want to buy their high school dream car are settling for the rebuilds.

In a few years their market is going to start dying off. That's why you see pre-war Packards, Auburns and Duesenbergs going for $100K now that went for $200K 20 years ago.