>> How do you square that with the fact that spending as a percentage of GDP is only slightly elevated compared to the historical average...? > Why should it scale linearly with GDP? I can see an argument that it should scale linearly with population (maybe), but if GDP per capita increases, you could also expect better tech/productivity to allow gov spending per capita to decrease.

Over time it _can't_ scale linearly with population, unless you decide to not adjust for inflation. It _could_ scale with population and inflation, assuming that you agree that you don't want more services from your government.

Don't forget, a percentage of that GDP increase is just inflation.

Most people, as they get richer, want to have services increase, as they can afford to pay more. For example, they go to nicer restaurants, nicer hotels, maybe they get a massage, where previously they would not have, etc.

This is largely also true of a population. We expect that our children will be better educated. We expect better roads/bridges/other infrastructure. Heck, we might even expect better public infrastructure such as trains, buses, etc.