15% is wildly far from reasonable. More than that, it's an entirely made up number.
There are arguments to be made that university budgets are too high (I don't agree, but they exist). So renegotiate indirect rates. There's a framework for doing this.
An across the board, utterly devoid of context arbitrary cut to 15% isn't a sane policy.
Your institution might have a large endowment. Mine is a rural state school.
Note: I was not typical. I set up as a digital nomad a long time ago. A scientist with a lab on campus who pulls power, AC, and other resources from central services, must have some way of compensating the university, and you could argue that instead of a prenegotiated (and amortized) overhead, it could instead be a cost center billing (scientist gets contract, uses campus resources, gets billed directly for their consumption). Don't forget also that because of Bayh Dole, the university gets monetize the IP generated by their scientists (who typically do not see any direct revenue; instead, they have to make a startup that licenses the tech from the university).
My experience with overheads showed that the universities I worked at had the highest (50-75%) while less prestigious regional universities were more like 30%.
Oh! This is new: I just looked up Berkeley's rates now and they explicitly have an off-campus rate that is 25%, while the on-campus is 60%. Apparently the federal government was already capping off-campus at 25%! I also see that funding agencies like Gates, Chan-Zuckerberg, etc, already cap at around 10-15%. Man, the deans must be furious
Ironically, prohibiting “breaks” to Gates, Chan-Zuckerberg, etc. and saying the rate they get is the same as your NIH rate would probably go over well. Most people I know in research admin are perpetually annoyed that private foundations act like being subsidized is their right.
Off-campus is capped because the grant is then paying for rent on the lab space from the private landlord. Universities don't charge research labs for power, cooling, rent, janitorial, Internet, etc. Maybe they will start now.
Some private foundations do charge less, but they’re usually not providing the bulk of the funding for a given lab. There are generations of researchers and American industries based on the model where NIH/NSF provide a stable foundation for research, and while that can change it’s incredibly disruptive to try to break existing agreements.
To put it in HN terms, do you know anyone who take lower paying non-profit work because they’re married to someone with a tech job which means they never worry about their mortgage or health insurance? This is like that spouse’s employer saying they’re getting a 30% pay cut.
When looking at the whole system it clearly becomes woefully inadeqate. To extend the example, the only direct costs of an airplane flight are the crew, the fuel/food, and any airport fees. Could you run the rest of an airline (training, ground staff, scheduling, booking, IT, maintenance) on 15% of the crew+fuel costs? Not even close.
If you look at federal contractors and other companies, the overhead on staff is probably closer to 100-200%, so 50-60% is very defensible.