Linux on the mobile has made some great progress in the last couple of years. A large part of this progress is thanks to the efforts of Jolla (SailfishOS), Canonical (Ubuntu Touch) and Samsung/Intel (Tizen).

Linux on the mobile can today make use of Android drivers thanks to libhybris (https://en.wikipedia.org/wiki/Hybris_%28software%29). The overwhelming majority of software that makes up "Linux on the mobile" is made up of mature FOSS components (e.g. Qt, systemd, Pulseaudio, Gstreamer, ffmpeg/libav, NetworkManager/Connman, Telepathy, oFono, BlueZ, rpm/deb, apt/zypp -- Wayland for SailishOS [and as of recently Tizen]).

I think at this point Linux on the mobile has a mature base. We now need a mature, polished, FOSS set of core applications. At that point (thanks to libhybris, and being able to leverage Android drivers) -- I think a self-sustaining community will be able to take over. I think we're about 2 years away from this goal.

I currently use Jolla (SailfishOS) as my daily driver, and I'm extremely happy with it.

I'm not trolling, but genuinely curious. Android runs on a Linux kernel, as does Tizen and probably several other phone OSes. What makes the Canonical phone more Linux than these for Linux fans? Presumably it's more like a desktop linux distro in some ways, but if so what ways?

Android uses the Linux kernel. That's where the similarities between Android and GNU/Linux end.

Ubuntu Touch is GNU/Linux. It is largely[1] made up of "standard" GNU/Linux components (e.g. glibc, systemd [soon], BASH, gcc, Pulseaudio, Gstreamer, NetworkManager, Telepathy, oFono, BlueZ, deb, apt).

This has several advantages:

1. People familiar with GNU/Linux can re-use their existing knowledge

2. The GNU/Linux ecosystem is developed by a lot of different parties. If you feel you can do better you can write your own components and swap them in (e.g. as Canonical did with Mir)

3. A community (or business) can develop their own "spins" (distros), which could extend the lifetime of your mobile (security fixes!)

4. It's a real pleasure to develop software on your Linux desktop, knowing there'll be less friction getting it to work on Linux on the mobile.

[1] The exception probably being using Mir instead of Wayland

Android development is not open (Google code dumps each release) and Android does not use the GNU userland based stack.

EDIT Also Android functionality is gradually moving into the propriety Google libraries.

Android basically forces you to use Java. Enough said.

Tell me with Samsung Bada. Not only the user experience was bad. Samsung was promising to update my old Wave to Bada 2 for at least 6 months, and then drop the support. It was the last time that I buy a Samsung phone. Now I'm very happy with my BQ phone that simply works fine.