OP is heading in the right track but hasn't come to the ultimate conclusion yet: PS4 and Switch are in different generations.
This makes them different for all sorts of reasons. For example PS4 has multiple versions while Switch only has 1. That is because Switch is a lot younger than PS4. Switch will have multiple versions eventually too. But Switch is young and still growing. PS4 is old and ready to have a successor. They are in two different generations.
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