The story of modern zoning is too long and complex to distill in one post, but to answer your question - no, that's not correct. Most modern zoning has its roots in utopian thinkers of the 1900s who had these grand visions of orderly "Radiant Cities", the key feature of which is that all the residential goes here, all the stores go there, all the offices go over yonder, and all the industry (read: jobs for poorer people) go anywhere else. The problem, of course, is that it turns out that real human beings don't actually like to live that way. Look at Manhattan: the places that were built at the height of this utopian thinking are the big housing projects where no one who has a choice wants to live. They're devoid of places to shop or work. The rich people live in places like Greenwich Village, Brooklyn Heights (just across the river from Lower Manhattan), Upper East and Upper West, which are rich with mixed uses and convenient access to jobs. Of course, plenty of people do want a big house and yard, but the trend over the past 70 years has been to try and impose suburban building formats EVERYWHERE and not allow neighborhoods to naturally increase in density as demand for density grows. San Francisco is like the universal poster child for this.
