So? You think someone is going to fund a startup and develop a fully independent, fully open source phone OS that will support modern hardware and all the apps stock Android does? Of course not. Jolla, Graphene OS and LineageOS show what a small company can currently do. You also have Ubuntu and Postmarket OS, Fairphone, Murena and couple more. Between them they cover all the niche markets: security, privacy, open-source, Android alternative and independent hardware. No one is investing heavily in them because those markets are really small. New startup trying to develop something from scratch makes no sense.