I suspect that may be part of the reason Larian isn't making a Baldur's Gate 4. At the very least, they probably realize that lightning is very unlikely to strike twice, so why tempt fate? Get out of the series while everyone still loves you. They probably also recognize that they would face a Knights of the Old Republic 2 situation where the IP owner will want more profit faster, and so they will set deadlines which don't fit with Larian's design model. At best, BG4 would be a rushed mess, with Larian struggling for years afterwards trying to deliver the game they wanted to deliver and burning down all of the goodwill they have built up with gamers. It's just not worth it. If they walk away and stand up their own IP, they get complete control and can take the time to deliver what they want to deliver. Sure, they don't have the built in fanbase that a D&D title would have; but, I suspect they are going to have a lot of that fanbase follow them anyway.

Sadly, Hasbro absolutely will be willing to burn down any and all goodwill BG3 has built up. I expect we'll see some smaller developer handed BG4, put under unrealisting timelines and the result will be a disaster. It will not be the fault of the development team. I suspect any dev team is going to be salivating at the prospect of making a D&D title. It's a dream project and they will bend over backwards to get it. They just won't realize, or hope they can avoid, Hasbro breaking their back in the quest for short term profit.