I, too, want competition in this space. Unfortunately, Tizen got some bad press this week: https://arstechnica.com/gadgets/2017/04/samsungs-tizen-is-ri.... The past year has not been good for Samsung on so many fronts.
I don't see many other options emerging. It's possible that a community-led effort to finish work on Unity 8 (and possibly port it to Wayland) may emerge, but that would only solve the phone UI issue, the main problem holding back open-source phones is likely to be closed bootloaders and lack of drivers. By supporting Tizen we can get Samsung to handle the low level stuff.
https://source.tizen.org/documentation/developer-guide/getti...
"This document provides information about how to contribute code to Tizen, including the following:
* Cloning over SSH
* Submit a patch to the Gerrit
* Review a patch on the Gerrit
* Submit a package to the build system
* Review and accept a package on the build server (for release engineer only)