I think that handhelds are having a bit of a renaissance but I think ultimately they will fade in popularity
PC handhelds are too big, heavy, and have bad battery life. I see mobile phones with telescopic controls like backbone/kishi or switch like joycon controls ultimately winning out. Console quality games are starting to be ported to iPhone and I’m sure android is not far behind. Emulation and cloud streaming are just getting better and better. Handhelds aren’t going to replace home consoles and PCs though, just supplement it, as it’s a device everyone already has