Here we have the "stupid" bit of my reference. No, the budget should not track population growth, because improved technology means that occasionally the cost to provide the same service to an individual decreases, whereupon the budget should also decrease. Or, for instance, a military threat or other transient event (eg COVID) that necessitated temporarily elevated funding levels expires, and the budget should decrease accordingly.

The converse being, of course, that sometimes transient events or large shifts (eg increase in costs of materials used to make some important good that the government procures) make things cost more, and so the budget should increase in proportion to those beyond population growth.

Improving technology has not increased housing stock or transportation options. Everyone still needs a place to stay and ways to get to/from work. Another issue is that using technology to reduce humans in the loop is what gets us "your call is important to us..." levels of customer support.

If the number of people who need to apply for id/license/passports keeps increasing, then the number of people servicing those requests also needs to increase (or we need to stop complaining about the dmv). No amount of technology is going to replace that need.