Retained even if the agencies work is no longer required in the volume of prior year or through automation or combining job responsibilities, can be performed with fewer humans required.

Generally that's not true under the Civil Service rules, though it can be true under union contracts. Government workers are protected from being fired for non-merit reasons, such as the new Administration not having "trust" in their loyalty. But if their job is no longer necessary, they don't need to be retained.

This is what, I think, Musk gets wrong when he thinks of the federal government. Employees are not really the cause of the government bloat he seems to despise. More than 70% of government employees work in defense or national security jobs, or in very labor intensive areas like medical facilities or border patrol or in penitentiaries. And overall, the federal government doesn't really have many more employees now than it did in the 1970's, even though the population has increased by around 60% and the economy has has grown 30x:

usafacts.org - How many people work for the federal government

The government is big because it spends big on programs, not on employees. Most of what the government spends is just sending money to people and state/local government. Again, to pick Department of Education (next on DOGE's chopping block), very little of its budget is spent on employees - almost all of its budget is student loans and funding poorer elementary and secondary public schools.