They allowed politicians to be a part of the process. Politicians know NOTHING about land use, management, etc.. Your city planner is a complete and utter moron when it comes to the job they have, city planning.
None of the homes need to be larger than 850 sq foot. Making a city self sustaining is certainly possible if you do three things.
1 - gather all leaders into one place.
2 - Lock all of them in a big room with no windows.
3 - let scientists and engineers do all the planning based on real data and real designs.
Sadly most people are dumb as a box of rocks and believe they cant be happy without a 5500 sq foot mc mansion and at least 2 acres of Kentucky Bluegrass that requires 10 gallons per square yard a day in water. So eliminate the people as well, at least the dumb ones.