I find that in AliExpress land, the long tail of stuff being sold (i.e. the stuff outside of the brand-names) was almost always created as a single batch by a process that can’t be replicated (e.g. because the people who made it only came together at that place and time to make that thing), and when that stock is depleted, the individual item is never sold again. If there turns out to be high demand, then
another product will be produced that will be
similar (sort of a knock-off, but sometimes it’s better rather than worse) but not identical.
One place you’ll run into this approach with higher-ticket items (i.e. not a $0.03 comb) is in the handheld emulation-console market. Some cool little device was created that everyone wants (e.g. the aluminum-alloy RetroGame 350)? Too bad, they can’t make more even if they wanted to.