Hacker News Reader

Mir is actually still alive and being developed at Canonical.

Ubuntu phone (the software stack of Mir and Unity8, running on Ubuntu, on phones, as opposed to a phone backed by Canonical) is still alive, usable and arguably the most mature of the FOSS "GNU/Linux on a phone" projects.

And in a few years you can just switch to flatpack or whatever it is that wins out, not like you're locked in for life just the packages exists as snaps today.

upstart was an rhel thing

Upstart was originally developed by Canonical. Several years after it shipped in Ubuntu, it was shipped in RHEL6. RHEL7 replaced it with systemd. While it probably had some RedHat contributions, to call it a RHEL thing does not make much sense.