To my (limited) knowledge, Larian and Divinity: Original Sin was made on a small budget, from a growing and fairly new studio and developer.
BG3 was a much larger budget, able to be made from their original success from Divinity's OS1 and 2.
Exactly. They did first break-even with DOS1 that was developed by a few guys in Swen's basement, and that poured a foundation to raise resources for DOS2. And then, Larian became huge company with multiple employees and offices around the world, they spent 6 YEARS (SIX YEARS, CARL!), polishing BG3. And people be like "Hey Swen, you know, BG3 is much better than Divinity. Brother do you mind making new Divinity a better game like BG3 because previous DOS/DOS2 were not so great, please?"
For real π