They got thier money for that system.
They don't get any money when someone goes home empty handed or buys something else instead because the store doesn't have any Switch stock. You can't rely on demand that's here today still being here months from now, you have to strike while the iron is hot. A lot of prospecive buyers will lose interest or choose an alternative, and those potential sales will be lost.
Bet with Liquidlaser: I say PS5 and Xbox Series will sell more than 56 million combined by the end of 2023.