How do they incentivize government employees into doing such excellent work without paying them a real tech salary?
They are contractors. The public face of Ghidra works at Praxis, for example.
Great benefits and job security, and a belief in the mission.
Use military members.
I was a special agent with an org involved in similar work. They put me through 7 SANS courses, including paying for 5 certs, in 18 months.