AOSP is Android in barebones so apps “work”, the thing is that most apps need services that are developed by Google on top of AOSP (google maps api, notificacion services, google pay) and that are hard to replace because they need costly infraestructure or years of constant development. On top of that Google is promoting/forcing the use of Google Play Protect so more apps need that layer now
There are already alternate app stores, and alternate OS and phones that are functional and niche. The real issue is that the Android people knows is not open source, AOSP is the thing open sourced, but thats far from what we use on a daily basis as Android, and Google makes sure every time it can to put hurdles between functionality and open source, some of those hurdles can and are being worked on, some others are out of reach for the open source community
I think it is its image of lack of stability and features; I know there are out there stable distros and almost every well known program has a Linux version, but the image that Linux has had through the years is not that. If Linux overcomes this and gets a better reputation, it would be a great weight lifted for the road ahead of the OS. I hope Proton breaks through the mainstream public and Linux gets more exposed and known out there
I have the feeling that the AI bubble isn’t going to burst as everyone expects, it will, but I don’t think it will restore prices to the good old days