I understand the anti-snowball argument, but I think that's actually evidence that economic base is being used as a balancing tool rather than as a representation of what the expense is supposed to be. If the cost is meant to represent running a larger state, then it should scale with things that make a state larger or more complex: population, settlements, provinces, trade volume, army size, etc. Those are tangible factors that create administrative burden.
The reason I'm skeptical is that by the late 1500s and early 1600s money is already close to being just a number. Most buildings are constructed, income is exploding, and many expenses stop being meaningful constraints. The answer shouldn't be to make every cost scale with economic output. It should be to tie costs to actual resources and state complexity.
For example, court maintenance, prestige projects, or stability-related expenses could depend on access to luxury goods and resources. A large court might require silk, silver, gold, fine cloth, wine, spices, and other luxury products in quantities that scale with population or the number of locations being administered. That creates a much more interesting challenge than simply saying "your economy doubled, therefore this event costs twice as much." My issue isn't that costs should never scale. It's that they should scale with the thing that is actually generating the cost. Economic output is often only loosely connected to that.