The reason politicians try to avoid shutdowns or only have short-term (1-3 days) is that they do not want the general populace to realize we do not need many of those government agents/agencies.
Essential services still go on.
I think if you could ever go thirty days straight with a shut-down...most everyone would then ask if you need 75-percent of the employees.
I’ve been in the military and the GS world, and seen the various angles of the overall problem. Probably 10-percent of the whole civilian force in DC are non-productive. They could pass from the face of this Earth tomorrow and their office wouldn’t really miss anything. This is a group of people who’ve established themselves....have a little empire...doing practically nothing but drawing a check and attending meetings.