Its not that hard to get (>1 million US citizens have TS), but not all clearances of the same name are treated the same by three letter agencies. The NSA does n

Its not that hard to get (>1 million US citizens have TS), but not all clearances of the same name are treated the same by three letter agencies. The NSA does not, by default accept, a clearance that you received elsewhere. The biggest cost to getting a clearance is time, energy and risk. The easiest path to a respectable TS/SCI is to join a TLA, pass all your background checks, pass all your lie detector tests, work there for a few years making sure not to do anything that could get your clearance taken away and then switch to the private sector. During that time you work at TLA you get moved to a project that uses technology that has little to no value in the private sector making it more difficult to make the switch. Disclaimer: I know this stuff from reading books and informal chats with people at tech companies, please apply salt to taste.