I’d argue it had far more to do with it being another one of Larian’s RPGs with significantly more production value.
You’re underselling how massive the Baldur’s Gate name is.
The exact same production in DOS3 wouldn’t have near the same runaway hype train.
Baldur’s Gate 3 outsold its predecessors by an order of magnitude. I think you’re overestimating the cultural clout that a game from 23 years earlier carries. Games just didn’t reach anywhere near as many people back then.
What they didn’t mention is that Baldur’s Gate is a Dungeons and Dragons franchise. DnD is magnitudes more popular than it was when BG2 released, to the point of being at worst nearly mainstream. What has sold people on BG3 is being able to play their tabletop game in video game form.
I do think Larian’s pedigree and the Baldur’s Gate name were contributors to its success, but if there was one driving factor it’s the brand recognition of DnD with the marketing of an AA to AAA game.
An order of magnitude with the difference of volume of game sales over time isn’t the giant improvement you’re portraying it as.
It wouldn’t have worked without a quality team, but Baldur’s Gate is every bit as much of a behemoth IP as something like DOOM. There’s a reason they worked so hard to get it. It’s sure as hell made them a hell of a lot more than the 90 million cut they gave Hasbro.