And people stay productive by enjoying hobbies and playing games. It's an investment in infrastructure, just like fire, healthcare, police, power, water, transportation, etc.

Also, most roads in North America are cash negative, with many cities building new suburbs with high tax to pay for the roads in the previous suburb which are falling apart, which were built to pay for the next last suburb, on and on until the first car-centric suburbs were built in the 50s and 60s. Low density housing rarely pays for it's public utilities directly, needing to essentially be subsidised by city centers to be worth it, and then you replace business with parking lots and everything gets so much worse...