Not that I agree with your parent comment or anything (I don’t), I use Helix so don’t really have a dog in this fight, I think it’s fine for them all to coexist.
https://groups.google.com/g/vim_dev/c/65jjGqS1_VQ/m/fFiFrrIB...
Vim 8 did add support for asynchronous jobs, due to the pressure of Neovim fork.
it’s pretty great to have my vimconfig give red squiggle in editor if i’m doing it wrong before i save & reload.
but i’ve not followed vim9 script as its evolved perhaps there’s a good type checker for it at this point?
even before neovim, there were vim extensions written in lua so it feels gravity of lua code has been considerable for a long time.
to me vim9script feels like perl5/raku split - evolution too late to grow new users, a remnant for a niche that will fade to oblivion slowly over the next 10 years.