Years ago I read about how Norway was redistributing agencies out of Oslo and into other cities across the country. This felt like it made intuitive sense, as you'd maybe get to distribute jobs to other localities and break up the concentration of bureaucracy. I haven't read about the outcomes, but I've always wondered what could happen if the DC area did the same.
On the other hand keeping all of the federal workforce in D.C, instead of the states, reduces the political desire to prop up federal projects just for the local jobs. Much easier to reduce wasteful spending when you don't layoff people you want voting for you.
The Maryland and Virginia sides have representation (which is very pro-government jobs, as they should be considering their constituency).