The Kawasaki H2 750 Mach IV tried to kill people. That is not hyperbole. The chassis, the power delivery, the reputation, the folklore around it: all of it added up to a machine the market judged correctly in the short term and incorrectly in the long term.
That is the pattern. The market is pretty good at identifying what sells right now. It is much worse at identifying what stays interesting.
The bikes that won by being sensible tended to get used up. The bikes that lost because they were odd, expensive, overbuilt, underdeveloped, or simply aimed at the wrong buyer often survived with their character intact. The market black flagged them. Time rescued them.
A Bimota YB8 makes no sense if your only lens is value per horsepower. It makes perfect sense if you care about a specific period of small-volume Italian ambition, and about owning something that explains itself before you even thumb the starter.
An RC51 was divisive because it ignored the prevailing four-cylinder logic and doubled down on being a large, loud, very specific answer to a racing question. Twenty years later, that specificity is the whole appeal.
Weird does not mean reckless for its own sake. It means worth a second look after the market has rushed past the first one. That is usually where the best stories are hiding.