Unfortunately only a 'gigantic conglomerate' stands a chance against Google and Apple. The other smartphone OSs - Ubuntu, Manjaro etc. - have a tiny market share.
Just look at how Firefox OS struggled even in developing countries, where it could run much better than Android in low-end smartphones. Then Reliance (a big and very cut-throat company) licenced it and now it has a decent marketshare in India. There are plenty of good alternative OSs, but without a big war chest they aren't getting mainstream acceptance.
I'm hoping the slow creep of right to repair laws will help with this. Forcing manufacturers to provide spare parts, documentation and diagnostic tools to independent shops I think will inevitably lead to more open devices in general.
There would already be a vibrant community of smartphone Linux distros right now if bootloaders were unlocked and manufacturers were more forthcoming with documentation.
very good point. the best use for that ewaste would be decent retreads for people who just need a phone and don't care that it's a few years from 'latest and greatest'.
I think there is more room with another Android based OS akin to FireOS, a fully Microsoft version of Android, with their desig language over top of what wouldn't need porting outside of Google based dependencies.