It is not a hard problem to solve and was/is being solved all around the world. If a developer is building not 60 homes but 6000 homes then they can be tasked to build a school, a few kindergartens, a fire station, cafes, grocery shop, a few bus stops and plenty of individual and communal parking spaces.
Going from single family homes to quadplexes does not solve the problem, build taller!
Going from single family homes to quadplexes does not solve the problem, build taller!