I agree that extensibility would be nice, but it cant / shouldnt replace the actually working software with all working features. Ive never been able to get into modal editors before helix because vim / neovim (probably kakoune also) are unusable in their base form by modern standards. Any actual config / distribution needs tons of work to integrate basic usability features and fall apart in a blink (and are usually not very performant - lazy loading exists for a reason). Therefore i think its the right move to focus on implementing a fully featured editor first and then explore extensibility. That said i will also be very happy when it becomes a thing, no matter if it will be via webassembly, lisp, ect…
Heres a neat easter egg: If you open enough tabs on firefox mobile the number in the tab icon changes to an infinity icon