Resolve/Resolve Studio and FCPX have significant presences as well.

I’d say its closest “competitors” are really Resolve and iMovie (much more robust than iMovie but same market more or less) since anyone who’s doing this professionally is going to pay for Avid/Premiere/Resolve Studio/maybe FCPX and not use kdenlive. Resolve is more geared towards casual use and hobbyists, while still being powerful in its own right (and free, of course).

Premiere is a (finicky) subscription based professional tool. kdenlive will never be a replacement for that and doesn’t strike me as an attempt at one.