Konqueror is at this point just one of many WebKit browsers. Last time I checked (2011 when having a chat with one of the devs) they had two devs working on it in their sparetime, which is clearly not enough for a project of that scale. Some time after that, Konqueror switched from KHTML to WebKit as its default rendering engine, and at this point, I don't think KHTML is around anymore (or if it is, it's only around in kdelibs to satisfy API compatibility requirements).

Konqueror never had more than about five developers at a time, and yet managed to build a better browser than anyone else - by keeping the codebase clean and well structured, and by being able to welcome outside contributions in a way that Mozilla never managed.

WebKit is KHTML, and since (as you say) it's the upstream rendering engine for many browsers, it makes sense for it to live in a "neutral" place; it's still an open-source project, and of course at this point it's had many contributions from outside KDE - which is how things are supposed to work.

If you prefer another WebKit-based browser then by all means use it - I've yet to find any that match Konqueror though. Just things like the integrated shortcuts from the context menu are better than anything else offers.