It could be also argued that if Vim wanted to keep the community together they could have just deprecated vimscript and adopted Lua.

Of course I am stretching things a little, I know.

I personally think Neovim's reasons for a fork are valid. They wanted some parts, not others, and they were willing to pull the work. So a fork is made. That is all ok. If my memory serves both projects have interchanged patches and improvements in both directions, so everyone has benefitted in some ways. The community (communities) will live on.