What needs to happen is effort put in to make other cities and towns attractive. This could mean encouraging commerce and industry to re-locate or set up new factories or offices. It certainly means ensuring city-level standards of health care and education, something that is a good thing to do anyway
Lastly there needs to be a campaign to encourage people to move to these places. Australia already has migration programs that require people to live anywhere other than the main capital cities.
Australia has a scarcity of fresh water, and low rainfall. Our inland rivers are dying because water is diverted to irrigation for farming; Sydney's water supply is pretty stretched and the option to build more dams is neither environmentally desirable nor possible, because all the rivers have already been dammed, and most are less than full due to low rainfall.
So without resorting to calling NIMBY, at what point can we say "we cannot support any more people"?
I suspect induced demand is more of an effect with highways than housing. People can change their driving habits from day to day more easily than they can change their living habits.
Expand a highway, and more people in the area start taking more car trips on it.
Add housing, and more people don't instantly come into existence to occupy it. (Maybe, over a few years, people stop cramming themselves into crowded roommate arrangements as much, and over decades they have more kids.)
But if I granted that induced demand applied to both...
Driving is a means to an end. People stuck in traffic are suffering.
Having a home is an end in itself. People need shelter, and living near your community/job/family is a huge quality of life improvement.
Plus, when you expand a highway, strictly more mileage is created. It's not like the additional car trips in this city are taking the place of car trips in another state. It's a net loss for society and the environment.
Whereas, when you add housing, even if it induces more people to move into that city, they're moving out of some other city, easing the demand in the housing market there.
