While certainly agriculture would not create large numbers of jobs, it would still be a good idea to combat the replacement of agricultural land with economically non-productive residential sprawl, as has taken over so much rich agricultural land in the Central Valley and in parts of the Midwest.
The American dream is to live in your own single family home. We'd have to have a major shift in societal values and expectations before people from all income groups will be clamoring to live in apartment buildings again.
That shouldn't matter. Proper public policy is about what is best (for the economy, for the people, etc.), not necessarily what the people want, which is often counterproductive and is why planning agencies tend to be far removed from the destructive reach of the voter.
In any case, the expectation is largely created by government subsidy and support for single-family development (and neglect for urban development) rather than some sort of inherent aspect of human psyche. The desires would change rapidly if government energy were directed properly.
Also, your objections make no sense, phknrocket. For one, Americans are certainly not obese simply due to producing a lot of food. True, low prices for some unhealthy foods contribute, but these foods are (1) not produced in California, where the most egregious loss of farmland is taking place and (2) heavily subsidized by the federal government, subsidies which must be eliminated or restructured for proper agricultural growth. Also, food is one of, perhaps the only, thing of which the US is a net exporter. We should play to our strengths to increase that advantage where we can.