I was in the military for 20 years, generally worked 80 hour weeks with no days off on deployment and at least 50 hour weeks when at home station, and received a fair salary on the low end of a comparable private sector salary for that job. I now make several times that just 3 years out and work half as much, so you could argue that the government was getting several times the salary I was worth from me. I observed the same in the vast majority of my coworkers, civil service and military, both in the military and in a civilian government agency where I was detailed. In fact since I've sat on both sides, I at least anecdotally can say that in my experience government workers are no more or less lazy than a large corporation private sector worker of the same level doing the same type of work.
Unlike most corporate employees, however, they are held to an insane level of scrutiny on the spending of every cent, which ironically often leads to suboptimal outcomes and to people like me leaving the government because life's to short to deal with being treated like a lazy bureaucrat when you're working your tail off. A quick story to illustrate this, just before retiring I was asked to provide a full audit trail three times over the course of a year on the same travel claim. It had been audited by three different entities, all mandated by law, which by definitions bureaucrats can only enforce, not make). I estimate that more money was spent auditing that claim than the total paid out. An achilles28 would mark that down to worthless lazy bureaucrats, I marked it down to lawmakers who share achilles28's view of all government employees as lazy bureaucrats who passed irrational laws that those bureaucrats had to implement because it was their job!
That's a concrete data point, although admittedly somewhat anecdotal. I often wonder how many actual human "lazy bureaucrats" the achilles28s of the world know personally, or if they're just parroting what they hear in their echo chamber?