Seems because of Supreme Court ruling practically every federal agency likely needs to be re-chartered to have the same structure as the Federal Reserve.
(Ideally we'd move towards Ranked Pairs voting too, diminishing the two-party stranglehold as well)
I don't think department heads were particularly technocratic, either. That was more supported by the laws/customs protecting the actual workers who didn't lose their jobs every administration. The heads were political - just political with an eye towards getting appointed/confirmed, rather than popularly elected.
The only thing that can be done is "re-chartering" the court – immediate significant expansion/packing followed later by drastic structural reforms.