Yeah, but distributors like Steam or Gog also promote the game to their regular customers (and the promotion grows as the numbers grow I suppose). So it's not a sure thing to say that it was better for Larian if everybody bought the game on the Larian vault......
More direct income (vault) vs. more promotion for a small fee per game (steam/gog). Hard decision imo.
Edit: I found this little piece of maths about selling games over your own store or over digital distributors in one of Swen's older blog posts:
To quantify this, here’s a quick approximative breakdown – a European digital sale of a 30€ game on a digital platform that takes 30% means the developer gets 17,01€ (56%) of the sales price (I took 19% VAT), as opposed to approximately 23€(76%) that he could make on his own store, taking transaction costs into account.
That’s a 20% difference, which means that for his next game, the developer’s team might be 20% bigger. Now 20% may not sound like a lot, but it is – there’s companies that move their entire offices to another country to get a 20% benefit.Wow, 20% more income is quite a lot. I think with this special insight I would also tend to use the Larian vault store. But if nobody buys the game on steam/gog there will be no promotion there at all. This could still mean that there are lost sales if people who would have bought the game on steam or gog don't have the knowledge of the existence of the game or of the possiblity of buying it over the Larian vault. Hm, still difficult....
