There are major exceptions to this, usually involving the city's potential expansion zone being bounded by water on multiple sides. Manhattan, San Francisco, and Seattle all have this feature -- and they've all developed into critical mass, where transit becomes required.

You cannot actually say that. non car oriented cities have been growing for hundreds of years, while car oriented cities only for about 80. You could well be right, but we will all be dead before we can actually state it with confidence.