Even “iconic” heritage is being whittled away globally. Monetised, written off, marginalised - whatever the reasons, it’s happening. I think only a few really old structures will ride this out over time - Stonehenge, the Colosseum, the Parthenon, the Kaaba - and post-industrial creations will yield.
Accordingly, fringe items will fade. It may not happen that fast but for many the relevance has been surpassed by illogical obeisance. When that is surely questioned, is the turning point. Some linger surprisingly, like ivory - why? (I have no suggestions.)
I don’t think it matters in this respect if collectible cars aren’t driven; look at the stashing away of 1959 Gibson guitars as an example of hoarding without use. It’s a slow burn but I think in time the rapid appreciation curve will tail off and eventually these things will approach parity with other items of indulgent curiosity.
Perhaps the short answer is, viability is not great if you intend to keep and drive the cars for the next 25 years…
