Given what he's saying here -- that Vim is in "maintenance mode" -- I don't think you'll need any formal merge. Neovim is just where all new development is done, and it'll slowly replace traditional Vim over time.
Not likely. The directions for the projects seem pretty distinct.
It should be noted that some original vi are still installed by default when installing some OSs.
The whole idea that a project needs to be in constant new-feature mode is just not reality. Just as one example: I'm still using the fluxbox desktop (about 25 years now), and it still meets my top level GUI needs for interacting with my workstation. I don't really _want_ it to change. I want the UI to be exactly the same after an update, so as not to disrupt my workflow.
Just like vim replaced vi, neovim will gradually replace vim. Being maintenance-mode software means only greybeards (and some stubborn holdouts) will stick to it over time and as greybeards retire, the new maintainers of linux distributions who are more familiar with neovim will make their choice.
Nailed it. Bram made the decision on his own and vim's fate is stuck with it. I was bitter about it but now I think it's best for both communities.
I doubt many 1980s mainframes were ever capable of running vim. People on 80s mainframes generally used mainframe text editors such as ISPF Edit (on MVS) or XEDIT (on VM/CMS)
Vim’s makefile does have support in it for compiling on Amdahl UTS, Amdahl’s Unix port for IBM-compatible mainframes, and so possibly vim could have run on an 80s mainframe running UTS. However, I’m sceptical there are any mainframes left running UTS anywhere on this planet-nobody uses it in production any more (apparently the last production users were some US telcos in the first decade of this century). I doubt any of the small number of still-working 80s/90s IBM(-compatible) mainframe systems in hobbyist or museum hands run it. There is a version available online you can run in an emulator, but it is an ancient version from the 1970s, whereas I believe the vim port is to a newer 1990s version-and I don’t believe any of those newer UTS versions are publicly available-either they survive in some private collection, or they’ve already been lost to the sands of time.