I encourage you to carefully read The Civil Service Reform Act of 1978, with particular emphasis on the Federal Labor Relations Authority (FLRA). Its law that allows federal employees to join unions. This should disabuse you of any notions that their unions can be easily “decertified”.
I agree with you that this would be a good thing to do. But the realities are that it would be exceedingly difficult to accomplish in our political environment. Like most things, its a lot easier said than done.
How did Reagan terminate 11k+ air traffic controllers in ‘81? There must be a way to overcome The Civil Service Reform Act of 1978.