> You pay for the cost of government elementary schools even if you homeschool your kids

and you receive the benefit of living in a society where most people have a minimum level of education. You can then hire these people and not have to pay to teach them how to read.

> You also pay for the cost of public parks even if you never use them

Maybe you personally somehow never enjoy seeing nature, I don't know. You still enjoy the benefit of a society where people get to see a little nature which is shown to make people happier and more productive, rather than everyone living in a bleak grey dystopian landscape.