You're way out of date Flou, Larian now has four studios with at least 130 employees in total.
They've been very successful. Unusually successful. Larian has been able to do things that other similar independent studios simply don't get to do, and it's unclear exactly how. I'd love to interview them about their financial state over the years, but I doubt I'd get a straight answer.
My suspicion - Belgian government support has played a role.
You don't think it has anything to do with the fact that Larian succeeded with their one big opportunity, while Obsidian more or less dropped the ball?
Both companies had to work for hire to finance their chance. Larian did it through education games, while Obsidian did it by making sequels for other companies. All in all, I'd say Obsidian was actually more successful working for hire, since the company grew a lot faster than Larian during the period, and still is bigger than Larian. Although the track record of their publishers isn't exactly ideal - with many publishers ultimately crumbling or failing to provide enough money - Obsidian has had a lot of offers, and I don't think you can say the same for Larian.
Then came the first big test: Larian's Divine Divinity Original Sin, and Obsidian's Alpha Protocol. Both in development for a long time, both new directions for their companies. Guess which company came out ahead of this exchange?
Obsidian has also had other opportunities. Much more so than Larian, they had an overwhelming amount of support for their first crowd funded title, Pillars of Eternity, which made enough money for them to not only make the sequel, but also got them support for Tyranny. Yet again, however, Tyranny proved mediocre. But hey, there's still Pillars of Eternity 2, and the new game they're working on which could be a new property.
So I'd say Obsidian has had plenty of opportunities. What they did with these opportunities is a different story. Divine Divinity: Original Sin was a work of genuine passion, and the market rewarded Larian for it. Maybe Pillars of Eternity was, too; but I have a hard time believing it.