I've switched from Vim to Kakoune 3 years ago, and lack of support for this modal editing style elsewhere is really frustrating. It is better than Vim's, but in practice that's not a significant difference, and the pain of switching back and forth is something I'm agonizing over all the time.
BTW. The exact kakoune modal editing mode is not even all that flawless. The way x and X work on empty lines is infuriating, and I am actually using a personal fork of kakoune to fix it. https://github.com/dpc/kakoune-dpc . I went so far as prototyping a spinoff of Kakoune: https://github.com/dpc/breeze to look for improvement, but building a full-featured text editor is a lot of work, and I it's not like it's going to fix the problem of switching.