Why would you want to start over with a new platform when Android (as a FOSS project) is already most of the way there in terms of freedom and usability? The only problem are "apps" that depend on proprietary Google libraries. This only concerns a minority of apps, but notably includes some foreign banks that require the "app" as second authentication factor.

Perhaps this could be regulated by law or executive power, but considering that governments themselves have created apps that depend on proprietary software, I am not too hopeful. But as long as the same "app" is accessible through a browser, this remains a minor inconvenience.