Replace many federal workers with those who are loyal only to the president

This is the key point that actually makes all this possible. From the wiki

It proposes reclassifying tens of thousands of merit-based federal civil service workers as political appointees in order to replace them with loyal conservatives to further the objectives of the next Republican president.

"Tens of thousands". There is absolutely not enough young republicans in the nation to replace that many federal workers. The outcome if they fired them anyways would be orders of magnitude worse than the De-Ba'athification of Iraq. Its declaring class war on Northern Virginia and its a fight the GOP would lose.