Well, some people think of museums as timeless - the sort of place we put 2000-year-old roman stuff, 5000 year old egyptian stuff, 200 million year old dinosaur stuff, and so on.
Of course, the practical realities of most museums are a rather different matter; rent and employees have to be paid, and land in tourist-friendly areas is seldom cheap.
I think car and motorcycle museums in particular live on the patronage of people who grew up when cars were symbols of independence and status, instead of a commodity. So the museums have nostalgic power for the customers, and that’s why they go. But that group is now 50+ years old, so I believe the lifespan of those museums is strictly limited.
Of course, the practical realities of most museums are a rather different matter; rent and employees have to be paid, and land in tourist-friendly areas is seldom cheap.