Well, only if you want to have empty units, as there's (almost?) always more than one person per housing unit. How many? Well, that depends on the wealth of the household, on how many children they plan to have, on how many generation will be living with them.

And where should those houses be located? That depends on the (future!) employment opportunities, on the surrounding environment, on personal preferences, etc.

And what kind of zoning should there be applicable? US-style sprawling suburbs? High-density skyscrapers? Smaller towns? How dependent is that on other factors?

What building materials should be used? Is it better to build something cheap for now, betting on improving economic conditions for later rebuilding? Or is a medium-term solution better?

If a layman like me can think of a few dozen variables in 10 minutes, how many are actually there? How can one make a plan that accounts for the particulars of each of the billion?