[arp242]

Whatever may or may not have happened in the past is not especially relevant. Today it's essentially impossible to enter the market as you will need to develop a solid iOS or Android compatibility layer, because the best phone in the world is useless without software (apps) you want to run. This is also a major reason several of those platform you mentioned didn't work out by the way.

Sailfish OS does exactly that, but it has a number of limitations and added friction due to legal and technical reasons.

And choosing between two systems is really not much of a "choice". Right now there is a story on the front page about Android app requiring devs to validate their ID, even for side-loaded apps.