That can just as well be marketing or a way to pad the price. 64 GiB microSD still costs ~$14 locally, but the same thing can be had for $4 from China without

That can just as well be marketing or a way to pad the price. 64 GiB microSD still costs ~$14 locally, but the same thing can be had for $4 from China without any warranty. They stick endless limited warranty on it and increase the price so much that it's economical for them to just replace a few cards that people will actually bother to return, and still make profit. And warranty will tell you nothing about quality. In fact on many products you can explicitly choose to pay more for longer warranty.