Civil servants are frequently working for the chance to retire after 30 years, with a life time pension, and the ability to start a new career in the private sector, often exploiting their government connections, and working for the contractors they once managed. This is often refered to as double dipping. If you do military, civil service and then private sector its triple dipping. There salaries may not be great but their life time payout is actually really good. Life time pensions are increasingly rare in the private sectors because they are staggeringly expensive with people increasingly living to be a 100.
If you actually compare private sector versus civil service salaries, civil service salaries are starting to outpace the private sector in many fields. This is partially a product of private sector salaries being stagnant in many fields for decades.
Certainly Wall Street banker and hedge fund manager out performs civil service. In the case of SEC civil servents they are usually there to do favors for the big banks and brokers they are supposed to be regulating and then they cash in the favors for high paying job with the people they used to regulate. There is a similar revolving door in just about every Federal agency. And yes it is also known as corruption.