Large systems have to invest most of their energy into surviving.

In biology, it's called basal metabolic rate (basic body processes) vs field metabolic rate (doing useful things).

Large systems grow complex internal processes that require a lot of energy expenditure.

In rockets, every pound of rocket fuel to lift a payload needs additional rocket fuel to lift the net new fuel (luckily, just a smidge less), ad infinitum.

In organizations of people, every additional person requires more coordination, which takes more people power to handle.

The largest organizations spend the vast majority of their overall effort just on dealing with internal organizational dynamics, not with producing externally-visible value.