MIT isn’t public, but you’d be surprised to find out how much of MIT’s operations are funded by tax dollars, mostly in the form of federal research grants. Research grants are very attractive to universities, because they fund salary and materials costs for individual researchers and their labs (and, thus, the university has to chip in less money for salary), but also because they come with “overhead” costs – a fixed percentage of the total money awarded for the grant goes to the university, and that money doesn’t all go toward paying the electric bills. MIT has negotiated a pretty plum overhead rate with federal granting agencies, and there are a lot of government dollars flowing into MIT.