Frictional Games studio?

[Googolplex]

I'm interested in how much money do they earn.
As I know, there were over 300.000 copies of Amnesia sold.
14 € per game (~10 € for the company) makes 3,0 million €.
I think, a half million is for the external workers like composer or soundstudios (if any).
That makes 2,5 million € for only 5 people, because they have no publisher.

But I see no Koenigsegg in their garages.