It’s largely a privilege for those who have both. not a solution for the economically depressed who have neither.

I'm pretty sure that's what Corporate Jesus would want people to believe. And to be honest, sometimes labeling something as "privileged" is just another way of reinforcing that thinking. It doesn't have to be that way.

1. Gardening does not require much time relative to the value of the output. Many new gardeners will say "oh but it's so time consuming" because they are still learning and make lots of mistakes. If you have your systems up and running and your processes down, it's a fraction of the actual value produced and is extremely efficient. Don't get me started or I will go on about this in extreme nerdy detail from personal experience.
2. Collective action can massively increase both the availability of suitable land and the output relative to any one individual's effort. An obvious example of this is community gardens such as the Gill Tract in Albany, CA. If Occupy the Farm had been better supported we the people could have had the whole thing, but there still is a large garden available for use by neighboring houses. And there are community gardens and vacant land waiting to be community gardens everywhere. It just takes folks to say they can do it to make it happen.

A key component in this is a general misunderstanding of the value of your labor. When you garden you retain 100% of the value of your labor and your time is worth much more. When you work for others and then have to pay for food at a significant markup, you are losing a very large proportion of that labor. This is one of the central lies of capitalism that forces you into wage slavery and promotes false narratives like "growing food is most efficient on a huge scale". Efficient to whom? Not to you.

Edit: Another related example is the Berkeley Student Farm on the Oxford Tract and 6 other urban spaces. They are doing some amazing work and it's worth a few moments to read about them: https://www.studentfarms.berkeley.edu/