My belief is that they didn't make enough motion control games. The last really significant one was Wii Sports Resort. This was released in 2009. After that, their core fan base of motion control gamers didn't get a whole lot. I think a lot of the games that were made to appeal to N64/Gamecube gamers were a mistake, e.g. Mario Galaxy 2 and Metroid: Other M. Instead they should have doubled down on more motion control games. They didn't make Wii U games to appeal to the Wii Sports crowd either which is the biggest reason why the Wii U flopped.
curl-6 bet me that PS5 + X|S sales would reach 56m before year end 2023 and he was right.
My Bet With curl-6
My Threads:
Master Thread, Game of the Year/Decade
Switch Will Be #1 All Time
Zelda Will Outsell Mario (Achieved)
How Much Will MH Rise sell?
My Bet With Metallox