Most of the time the roads are built with grants from the state or federal government.
If they didn’t have to pay for the roads to begin with they have 30 years to set aside money for the replacement. Even minimal interest would drastically reduce their out of pocket costs. Grants turn this into a question of bad fiscal management, which is definitely an issue but says little about how much infrastructure they have.
It’s also not the developers job to consider the long term maintenance and tax implications of these developments. That’s the responsibility of the city itself through plan approval and zoning.