I believe the reason why people aren't out here trying to make compatibility layers that make a PC play console games is because it's just plain impossible if the CPU architecture is different (x86 vs ARM, for example). And even when it is possible, I believe that compatibility layers can take a lot more time and effort to create than emulators. Which I think is how the whole "will Switch 2 have BC?" thing even started; a YouTuber pointed out that making a compatibility layer can be an arduous task when they were going down the list of options Nintendo and Nvidia had for Switch 2 BC, which developed into people thinking "well, if it's hard, they just aren't gonna do it, then."