Switch's attach rate is now 8 games, which interestingly is more in line with Nintendo's home consoles than their handhelds, which had lower attach rates.
If you subtract Wii Sports as it was a pack-in with almost every system, the Wii is also at 8 games per console, as is the NES, the two most successful of their consoles.
Bet with Liquidlaser: I say PS5 and Xbox Series will sell more than 56 million combined by the end of 2023. (And over 130 million lifetime)