>>712612275They did indeed make "a billion" of them, the delayed the console an entire year to make sure they have millions of units in stock on launch. Normally the console was ready for shipping by early-mid 2024. Maybe as early as late 2023. But that means they have done nothing but churn out Switch 2 hardware for like the last 12-18 months, all for launch day.
However, backwards compat. may not have been fully finished yet, so they definitely also delayed to make sure (almost) every Switch 1 game works on it from launch day on, that also was part of the reason for the delay.