I suspect I had mixed up federal and total tax revenue %. We're still only talking an avg of $4k per working person for the entire system though, if you take the total funding sans property tax and divvy it up by the working population (90bn, ~30% prop tax, 16.9mil working pop).
I realise the avg isn't going to be representative of the general population, but the marginal utility of money should roughly scale with the amount of that paid per-person.
> Grocery store people work and have contact with far more people.
Honestly not entirely sure of your source on this. I'd suspect that having several hundred students in the same building for an entire day with central AC would be more of a petrie dish than your typical grocery store most of the week.