It doesn't look like it's the case with Vim - https://github.com/neovim/neovim
The wiki gives a good overview of the problems with current Vim https://github.com/neovim/neovim/wiki/Introduction#problem
I read about Neovim on HN when the developer (Thiago de Arruda) was crowdfunding it to make it his full time job. I remember Bram had refused (ignored?) a few pull requests from Thiago, which is one of the reasons for Neovim.
I was wondering whether Neovim would end up as a one-man endeavour too, but it seems like a pretty lively project with loads of other people involved - I'm really looking forward to seeing where it goes next.
No. Vim is opensource and developed by a community.
Perhaps an amazing text editor is a project that's easily given to being a one-man-show. A single developer writing code and then thinking, "I need to make myself a better tool than this".