these companies make money when nasa sends stuff into space. If more stuff goes into space, they make more money.
(the money comes out of the government's pocket in this case)
In the US, people are becoming increasingly tolerant of corruption. These days it more often invokes funny euphemisms than action. Politicians have innate incentive to fall into corruption, and it's expected that some of them do from time to time. But, it's the people's job to keep them in check.
If this country values funding science, then it should let the scientists determine where and how the money should be spent, not politicians, not lobbies.