The difference between all those and stamps is that the former offers an experience. UO sells a lifestyle, and objects like stamps don't convey a particularly exciting narrative within that.

Not only that they provide an experience, they are also subject to wear and tear while doing so. The supply in historic stamps is a lot more stable than the supply in historic mechanical things that some may actually want to use.

Cameras may be obsolete, but old camera lenses can be adapted to modern mirrorless cameras pretty easily, and usually they last more than camera bodies. There are some 70s/80s ones that are pretty decent even for modern standards, plus they have a look that modern lenses don't have.. so prices are rising..

Camper vans are on the rise.

And have been for almost a decade now.