The game cost $5,000,000 to make. Assuming Obsidian did something really dumb like give Paradox 50% of the post-Steam revenue, they've already made $5,000,000 after taxes.
Are you their accountant perchance?
I don't make wild guesses, I look to the behavior of the various studios, Sven decided to expand his studio activities and projects thanks to D:OS sales, PoE has not even got near to the time of permanence of that game in Steam To Ten sales.
Using rough estimates.
They're are at least 350,000 owners on Steam, according to SteamSpy. Given the Kickstarter achievement (14.8% at time of writing), that suggests 52,000 of 77,000 backers activated on Steam. That's a fairly believable number, so I have no reason to doubt them. So, we're to drop that to 300,000 in sales. Also, backers like Sensuki bought like 20 keys to fence for 20 dollars a piece, so I'm going to drop 10% (30,000) because cranberries.
However, historical trends (using mostly the Witcher franchise as an example, but also other games) indicate that 20% of early sales for an RPG of this type should have occurred on all of the other digital retailers, 16% from GOG and 4% from everyone else. So we're going to say 60,000-80,000 copies have been sold outside of Steam, tacking on some additional sales because of its association with the well established Infinity Engine/Forgotten Realms metaseries on GOG.
That's brings us to about 330,000-350,000. Multiply by $45 and you get about $15,000,000.
Steam and everyone else get 30% right away. Good-bye 4.5 million.
That leaves 11.5 million. Let's assume Paradox gets half and Obsidian gets half.
5.75 million each.
Taxes on software entertainment companies in the U.S. are about 14% state and federal.
So you lose 805,000, thereabouts.
Leaving just shy of $5,000,000.
However, a few tens of thousands of those sales were royal edition and/or upgrades, which would explain revenue remaining competitive with GTA5 for a week despite such a hugely lopsided difference in sales.
So we get over 5,000,000.