But, I can see that the scope of such an endeavour would be too big to do it "for free".
BG3 did really well. If they wanted to support BG3 longer they could have. I really doubt it is lack of financial incentive that makes Larian move on, but lack of creative interest on their part. If money would be a concern, they would work on BG3 further, or a sequel. In fact, initially they were considering more content for BG3, before deciding to move forward to new things. https://www.ign.com/articles/larian...-gate-3-dlc-expansions-or-baldurs-gate-4
Sticking with BG (be it DLC or sequel) is what revenue driven developer would do. If Larian wouldn't fulfill their vision for the game, they might have tried to remedy that. I didn't get an impression that there wasn't much that they wanted to do, and that they didn't have time/resources to do. AND BG3 did get a solid post launch support with what seems like a years worth of fixes and new epilogues and modding support.
