There are plenty of supposed Steam Deck killers available in the portable gaming space, from the Asus ROG Ally to the Lenovo Legion Go and all the Ayaneo and ONEXPLAYER devices in between. But none of them have managed to outright slay the dragon that is the mighty Steam Deck yet.
I totally agree, consoles a better for simply running games because the entire UI/UX is designed to run games. But it doesn’t really make them less finicky. There are still separate build with separate bugs. Cyberpunk was buggy on PS5, right? And with PC you’re free to upgrade to whatever specs you need. With consoles developers have to try to adapt their games to fixed, sometimes years old specs and the results can be not great (like with Zelda).
The point is that a PC has a million possible configurations that can affect performance. A pared-down environment, like gamescope, cuts down on most of the software-side issues that a PC deals with.
Yes, just installing a game on Windows and running it is pretty simple, but these days lots of games have anti-cheats which can be triggered by other software running (or even just installed) on the computer. Windows on its own has a ton of overhead due to all the background and telemetry processes always running.
A console forgoes a lot of that background stuff, and limits the hardware compatibility issues by being a fixed environment. Your game only needs to run on one specific combination of hardware for each console it’s released on. In that sense, it is a lot less finicky than running it on a PC.
You are talking about hardware deficiencies more than anything, you can get those on PC too if you just run low-powered hardware. I’m more talking about bugs. Maybe it’s changed since I used Windows years ago, but I remember having issues from time to time with PC games. Crashing, weird behavior from alt-tabbing, some games just running at low GPU usage for no reason even though framerate is uncapped, and various glitches. There’s a reason there has been a growing interest in sandboxing for software with docker, etc. Software is deterministic, if you give it a consistent environment it will do the same exact thing every time.