I found BG3 to ultimately be one of the most disappointing gaming experiences I've ever had, and I wouldn't have bought a DLC even if one had come around. But I still feel strangely sad about the news that it's definitely not coming. I'm definitely not buying another Larian game, their style just does not work for me, but I can see a lot of people saddened by this news, and I share their sorrow. But Larian is well within their rights to step away and I don't think they're doing anything wrong by doing that. Not diong DLC certainly doesn't mean "cutting and running." I expect they'll finish up patching the game, I don't think it's crazy to expect a definitive edition in a year or so (less likely now than before, but still not out of the realm of possibility) and I think that's fine. Let the game end, let Larian move on. Let this just be a good game that existed and you had fun with.
Personally I've always had a suspicion that Larian really like Baldur's Gate, but they don't care as much for D&D the system. That seems pretty reasonable based on all I've seen around.