Because as proven since OpenMoko that isn't what the general public wants, tiny Gtk and Qt apps, alongside a UNIX shell.
Also if you only appeal to those that care about having exactly that, the sales will never be high enough to keep a sustainable business, unless it is at the scale of a phone vendor at least like Jolla.
Also if you only appeal to those that care about having exactly that, the sales will never be high enough to keep a sustainable business, unless it is at the scale of a phone vendor at least like Jolla.