My personal answer is because my audio/sound setup is obnoxiously complicated and I’ve tried to get a variation of it working on my steam deck but never managed it. I’m sure there are ways to do it, but on windows I know how it works and how to fix it if some update breaks it. If I switched it would require a lot more fussing around and special software that may or may not continue being supported and I just don’t want to deal with it.