Munchkin Quest is a brilliant and unique Crawler, I am not sure why it never caught on as much as I thought it would.
I of course cannot speak for SJG. But I suspect C'MONs Munchkin Dungeon might be the nail on the coffin for Munchkin Quest. Luckily I think the two expansions round out the game very nicely.
Also, if you haven't seen this, it is (or was) the official stance:
https://munchkin.game/news/2019/june...s-almost-over/
Good news is the base game and second expansion are still available through Warehouse23. :)