The people I know leaving that sector have been steadily leaving for years due to the day to day bullshit/internal politics and poor leadership that they have to put up with, not the pay nor current administration.
The first thing they are going to see is the salary and run a mile. That's partly why Palantir 'works'; they pay tech salaries and have a tech culture, but do gov work. Booz Allen et al were less advanced prototypes of that as well.