We still need farmers in rural areas who will of course use more than their share of resources, but the number of farmers we need is small and so insignificant. It is the semi-rural suburbs that have enough people to make a difference.
Take for example food. When you're on the countryside, it's not complicated to produce more than 90% of what you eat locally (up to 100% for people willing to give up on some spices, oil and other products not grown locally). What makes it complicated is that local farms were coalesced into big industries based on monoculture (which itself destroys the environment) so the food produced on the countryside doesn't feed people locally but serves as a source for big corporations to make derived products (usually less nutritive and bad for health) which rural and urban people alike will go buy in the supermarket (because there is usually no more alternative).
So i agree the current numbers don't reflect that so much, because of the self-perpetuating circle of heteronomy imposed by capitalism. But living on the countryside relying on local production is way more eco-friendly than any industrial civilization could ever be.
Is it, though? More than half of cultures are used for animal exploitation (which most of the world could do without). It appears we currently have around 2 football fields of cultivable land per person living on earth (though this may change soon with the climate).
We also have to take into account that industrial farming and monocultures kill the humus and dry off the land in the long run (over decades) making it more and more sterile (requiring an ever greater dose of fertilizers to grow anything and making the crops more sensitive to heatwaves).
Many serious agronomists (those not employed by the industry) insist not only that another agriculture is possible, but that it's the only way to prevent food shortages in the coming years (which will happen if we insist on chemical-powered monocultures).
Also, a one-garden-per-person model is not the only way to grow locally. We can of course share the land and the work. It just makes things a lot easier when the population isn't so dense that you can't grow your own food locally anymore (which is only the case with big cities).
