(a) step increases? (Hard to believe; these are small but generally unpreventable)
(b) quality step increases (again small but it takes action by the supervisor to get one)
(c) grade increases? (not just action by the supervisor but also the supervisor’s supervisor, personnel, et al.)
(d) promotions to Senior Executive Service?
It’s a mixture of all four I suppose. The Agencies dealing with high-tech matters have to pay people salaries comparable to what they could make in the private sector just to get them on board.
Someone who can make >$150k with a private company isn’t going to work for the gov’t for very much less even in exchange for job security.