I think the kind of success that was unexpected was the “above the AAA catalog” kind.
Games like Zelda sometime take sort of 11/10 on some magazine’s review, and then they shut up (because those 11/10 come usually from some Nintendo’s shill reviewers: they shut up to avoid see their BS being called over).
BG3 was bragged unanimously as some sort of holy thing… and they are still going.