Nintendo, just like Sony and Microsoft are companies that only care about one thing, making money. Its as simple as that.
This time around, Nintendo can afford to not care much, because the switch is very successful, Microsoft on the other hand, needs stuff like gamepass and backwards compatibility to regain lost market share, Sony doesn't need to do anything really.
Everyone talks Nintendo, but you cant even play ps1 or ps2 or ps3 games on ps4 or ps5, streaming doesn't count due to poor performance and the need for a fast internet.
Even the xbox plays enhanced ps1 games.
BC was always a thing with Xbox, the handfull xbox games that you could buy digitally were available to play on your 360 with your account and the bc 360 program was in the works while the 360 was doing great. The Wii was praised for its VC so critizising the Switch for not having it is fair. I really don't understand how people can call 'the ability to play games you bought before on your new console' a weakness. It should be mandatory by now.