As much as I hate to say if, trying to low ball Larian is probably a good business decision. They are studio with niche appeal (out at least they were, before bg3 released) and I have no trouble believing MS would have the upper hand in negotiations.
Making an agreement to release a game on game pass basically means betting against the developers on their own success. The game might be huge. It might be a flop. Whatever happens, the money from MS it’s going in the back.
I don’t think they were lowballing; I think they genuinely complete underestimated Baldur’s Gate 3. Their internal documents comparing games coming out classified it as a “second-run Stasis PC RPG.”
I can’t really parse the “second run”. Was it supposed to be Stadia exclusive for a while and is the list never updated? Do they mean the early access release?
Either way, Microsoft never really “got” gaming in any meaningful sense. That’s why buying Nintendo and/or valve would have made sense, those two really understand their respective markets.
I believe Second run in this context refers to getting the title on game pass after it leaves Stadia exclusivity. This document is pretty old, probably originally written while Stadia was still around.