I mean, seriously, this is not that surprising. It seems like Nintendo delayed the hardware 1-2 quarters to allow for more time to produce more of them ahead of release, and even imported many of them to the USA at least two or so months in advance to avoid all the tariff uncertainty.
I guess the only surprising things might be how quickly it sold out in the USA. Japan was almost certain to sell out, given the pre-order "disasters". But the USA selling out typically being Nintendo's largest market was not as certain. That said, the backwards compatibility and essentially upgrades to 4K+HDR capabilities, was pretty certain that it would be a good seller, even at the higher price point than people had been originally anticipating (I believe fans were hoping for a $350-400 range, but given that it has essentially sold out within 2-3 days of launch across the country at $450, it shows the market could support that price).