It's a different budgetary item. Unlike a household budget where people are given a general income and then asked to decide to spend it on housing, gas, groceries, etc. It's far more like SNAP, where the money given to you is legally bound to very specific things-- you can buy baby food but not diapers for your baby.

I’m somewhat skeptical of the idea that salary money cannot be shifted around.

Grants paying for PhD students- sure, those cannot be shifted to pay for admin; that makes sense.

Are administrators line items in the state budget? Then this would make more sense.

I'm certain that has cuts continue, admin will begin to be laid off, but it makes total sense that the first response to grants being rolled back is that the things that are directly funded by grants (NOT ADMIN) are also rolled back.

To continue a SNAP example: it makes total sense that when you have less food money, you buy less food. You may proceed to sell your used video game consoles later but the very first thing you do is reduce your spending on food.

At most public universities, the tenure track faculty, staff, and admin are primarily jobs negotiated through the public union. They are paid for by tuition revenue and state funding. They cannot legally be cut, and almost always are directly related to the teaching aspect of a university.

However, universities do research, and need research infrastructure. This includes administrators, safety people, compliance people, core research facilities, etc. Those are usually on what is called "soft money" - funds from IDCs. Those folks can be eliminated, of course, but there are typically very few of them and they are serving the most essential roles. If you eliminate them, you may need to eliminate your research program altogether. The NIH requires you to meet safety standards, the EPA requires specific waste disposal, etc. The folks that ensure that compliance generally are paid for by IDC funding.

I would not characterize it as “most”. Most universities in the US don’t have unions.

It's even more specific than that. Grants are often specific to a research project and you're not supposed to pay, say, a postdoc that works on X with a grant that's supposed to cover work on Y.

Cutting admin people might mean more paperwork for professors and researches, which can lead to less grants and funding because you can’t do science while doing paperwork. Not that easy to be efficient without losing productivity.