They said "huge success". Huge successes in text editors are Vim, Emacs and maybe Sublime. And do you have anything to backup your claims about neovim's popularity?
One measure is the number of stars on github and active contributors 49.7k vs 25.7k and 737 vs 79. The other measure can be the number of new extensions being written for each of them (particularly extremely high quality ones like telescope). Searching `nvim` on github yields many plugins which are advertising the Neovim editor by having it in their name, some of these are even ones which support vim e.g. Shougo/denite.nvim all of which point to the fact that neovim is a huge success and is on tract to overtake vim. It would not be an exaggeration to say that a lot if this is due to first class lua support in Neovim. By adding nice features like treesitter and LSP it has become an improved version of vim, an editor that actually understands the code being edited beyond simple text objects (e.g. https://youtu.be/E4uaPs9e9UU?t=68)
It's not as popular as vim per say, but it's definitely catching up. It's kinda silly to suggest otherwise.