I am a businessman, who follows this business.
What we don't know how much cut retailers get of that 50 bucks.
Or Microsofts cut
Or Lucasarts cut
Or Obsidians cut
What we do know that is 780,000 sold as initial numbers is good for everyone involved.
As for the box office list, there is the NPD list, which tells how much console games have sold, but you have to pay for them, unless they get released to the public. No numbers are kept publically for PC games.