It appears that the Unity desktop is more popular than a lot of people thought, even Canonical itself. According to this (http://www.omgubuntu.co.uk/2017/11/ubuntu-unity-remix) article, a proposal to create a new community Ubuntu flavour based on Unity 7 is gathering support within the Ubuntu community, and has already won the backing from several Canonical employees, including none other than Martin Wimpress of Ubuntu MATE fame. Discussions are underway and though in early stages, Canonical has given those involved their blessing to use the “Ubuntu†trademark.
This article really made me smile. I'm might be the only one in our small Linux community to think that Unity is a great desktop, but even after working with the default 17.10 gnome which has been made to look like Unity, I can still see some advantages of Unity over gnome, and both over any of the other Windows or Mac-like desktops. I do hope this "Unity Desktop Remix" moves forward, as I haven't, so far, found that the current version of Unity, added to gnome on Ubuntu 17.10 works all that well (at least not on my 2015 iMac).
I told you that a group would probably pick up the reins and continue Unity. I can't even stand the Gnome look-alike but lots of people like yourself like it so I imagine it'll continue on. It's all about what you're used to. And since it's still available in older versions now, they have a solid base to move forward on. How much work it involves to maintain and update it, I have no idea though.