Detta är en vy från en användare från reddit community of TBBT , vilket är ganska övertygande nog:
He's demonstrated that he's not interested in money. He's got a stack of unwashed paychecks in his desk drawer and this past season he offered a significant portion of his share of the patent money from their gyroscope to Howard.
In the linked post, there's a reference to Sheldon saying "we could be rich" but his head wasn't right then.