I have a Steam Deck and I'm happy with it too, but my point is that the game compatibility would just get even worse if you add on having to emulate x86, because it's not like x86 emulation would be perfect right away, and the amount of native ports will become even smaller than they already are

Even if the architecture is an improvement, in practice it wouldn't make any sense right now, and I can't see an ARM-based Steam Deck or whatever selling nearly as well as the existing x86 ones given the downsides it would present