I'd say you have it exactly backwards, although it may just come down to differences in terminology.
Windows phones (small P) are devices that run MS' mobile OS, either 'Windows Phone' (capital P) or 'Windows 10 Mobile'. WP 8.1 was the precursor to W10M.
The marketing term or brand "Windows 10 Mobile" is dead. The technical bits and pieces that made up W10M are NOT dead. W10M itself can't be dead, as W10M is just a subset of W10, which is very much alive. The differences between W10 and W10M are these:
- W10M and W10 have different shells. Both currently used shells will eventually be replaced by CShell.
- W10M ships without Win32.
That's it.
Everything else (except for drivers), is identical between W10 and W10M. For that reason, getting rid of W10M would literally mean getting rid of huge chunks of W10 and that isn't happening. It's ironic that after two years of WCentral steadfastly claiming that W10 and W10M are the exact same things (which isn't true either), and most people believing that BS, people now can't see how only one of two identical things being dead is a contradiction. If they are the same thing, then they must either both be dead or neither can be dead... technically.
Sometime down the road, MS will release a "new" OS that also lacks Win32. That is all W10M really is. W10 without Win32. This "new" OS will come with a new layer of paint (CShell) and we won't call it W10M, yet that is exactly what it will be.
Phone hardware on the other hand, MS is done with that... MS might decide to launch something in a similar form factor, but it won't be a smartphone, in the same way a 2-in-1 (convertible) is neither a laptop nor a tablet.