>It's not some god given rule that cities HAVE to keep growing ad infinitum, especially ones that have limited land. Most San Franciscans are happy with the size of the city as it is.

If the population of the country is growing then those people have to go somewhere. You can either suburbanize the wilderness or you can let more people into existing cities, and while I can understand the desire of the people living in San Fransisco not to share the nice things they have I can't say I sympathize.