The civil service system was ruined by public unions.
It worked reasonably well up to the 1960s-1970s. Then creeping unionization (JFK’s EO & LBJ codified it into law with legislation!) and it’s been downhill ever since.
Another mistake that was made was ending the civil service as a separate non-departmental commission. By doing that it lost its “independence” even though by then it was gone somewhat in practice by the creeping unionization. However, keeping it separate would have made it easier to restore that “independence”. Placing the civil service under the executive branch makes it much easier to politicize and allows unionization to grow.
With it under the executive branch Trump or DeSantis can with a EO make it all “Schedule C”. It is a solution but not a good one because the next Rat administration (and there will be one!) can simply undo that EO. Putting it back into a separate commission with appropriate legislation would make that harder