> The only brand I even recognize is Finish, and they're a UK firm, not American
Plenty of non-american firms sell products in the US. Like... I don't know, Nestlé?
I watched the same Technology Connections video. He does mention Bosch dishwashers by name. Those are available in the US. It's just that people barely bother understanding how dishwashers work, let alone _very infrequently_ refilling the salt. Heck, people drive without checking tire pressures, dishwasher salt has no hope.
Not surprising that most stores don't bother. It lasts forever too.