we'll soon see I think, Valve has said they want this to be more of a traditional console-style lifespan, and they've also said they don't see a reason to release a Steam Deck 2 unless they can get a significant performance bump, as of right now having a hardware target for devs to aim/optimize for is a really good benefit
plus if the devs optimize a game for Steam Deck those optimizations help for other handheld gaming PCs even if they're more powerful than the Deck
I'm super excited about a potential Steam Deck 2, I would love to see a better screen (quality, not so much resolution, maybe OLED) as well as a better battery life, and, of course, a more powerful APU... I wonder what the possibility of porting Proton to ARM is and switching to an ARM/Chiplet style CPU for the Deck 2