Steam Deck could be awkward for Sony and Nintendo
I had a PlayStation 2 back in the day (mostly to play DVDs). I couldn’t play any PlayStation 1 games on it. When I got a PlayStation 3 (mostly to play blu-rays), I couldn’t play any of my PS2 game on it. There were a couple of exceptions — I bought Shadow of the Colossus a second time, to play it in HD at a decent framerate, because it’s an astonishing work of art.