There are more details that make me believe that linux as mobile OS is more feasible in near future. Apart from the Valve&SteamOS push, the one notable phenomenon that I see happening is retrogaming. In retrogaming handhelds ecosystem there are now many devices with form factor close to phones (they often literally use screens from older iPhones, etc) that are running on Linux or in some cases provide option to easily switch between Android and Linux. For example on Anbernic RG35XX using Garlic OS there's a toggle in the UI to switch between Android and Linux. Similarly Retroid Pocket 5 allows switching in the bootloader menu.
As a separate point, it seems quite feasible to run Android apps in VM on Linux based phone and make the experience fairly seamless. Something like what Waydroid provides.
It looks like the combination of PostmarketOS (based on Alpine linux) and Waydroid would seem to fit that.
> As a separate point, it seems quite feasible to run Android apps in VM on Linux based phone and make the experience fairly seamless.
But why?
The premise of Waydroid seems to be to bring Android apps you want to your Linux desktop. But why would you want the phone in your pocket to run Desktop Linux so that you could then run Android apps on your Desktop Linux mobile phone instead of just running Android on your phone?
What desktop Linux features do you want on your phone that would justify this complexity?