Voluntary funding does not work, and honestly the same people that argue against taxes would turn around and say "I will only pay for the street in front of my hose". And the problem will begin again.

1), just getting the budget for things is work. How would you pay for the proposal and the organization to do it? You can't just say " it should be included in the price" because then with a few assholes in the neighborhood that don't want to put any money, not only you don't get the street, but no one want to make a new proposal.

2) if you fund the streets for your neighborhood but no one funds the ones between it and your work, then it still sucks

3) this approaches leaves poor parts of the city even worse off as now the can't get any repairs done because they don't have the money for it. Poverty CANNOT be a feedback loop where being poor makes you poorer