Re: Renaming and discontinuing
I think renaming is sometimes advisable because the projects aren't run from the same group. For example, the Lomiri devs aren't the same group as those developing previous versions of Unity, they may not be maintaining compatibility with old versions of Unity, and they're making a different product. For example, distros that are still shipping the Unity desktop are using older versions of the software, built with the desktop in mind, and this version is intended more for a small touchscreen interface. Not that you can't use this version on a desktop, but there's probably a reason people aren't.
When a big enough change is made, it makes sense to not have multiple projects with the same or similar names. In an ideal world for me, the name would be meaningfully changed if the project isn't trying to upstream their changes to the original thing by that name (the reason why neither WebKit nor Blink are called KHTML even though they both started there). It helps someone know which project is the original and which one took a different path, especially when they have diverged enough that the two pieces of software aren't compatible with one another anymore.
I'm afraid I agree with you about the reliability of Linux-based smartphones. I'd like them to get here, but I wouldn't count on it happening. It's a slow process, and a process that may not be able to get fast enough to ever become useful the way Linux on a desktop or server is. Even the technical user sometimes wants to use a phone to call people, and if it isn't reliable, they'll become annoyed.