well you're unrealistic to think that producing ALL of the food a family of 4 eats is anything less than a 40 hr a week job for somebody in the family. we're not talking about a little fresh veg for the salad, we're talking literally a ton of food. you don't just throw some seed in the earth and stand back. it has to be cultivated, harvested, preserved, stored, rationed, etc. when pioneers were surviving on their own crops it was a full time job for the whole family, and if they were lucky they had a little left over to sell and improve their lot.
and where exactly would the residents of nyc , LA, London, or tokyo get a few acres to grow their food?
we could be doing alot more than worrying about food depleting our fossil fuels. we could all live within a mile or two of our work, travel by foot or bicycle, and eliminate ALL personal autos as transport. but we're not going to do that either, as a species we will continue to consume the planet's resources like locusts until depletion forces us to find another way. that's the only given in this equation, our insistence on free will makes us all prisoners of inertia. embrace the suck!
You're right in a lot of what you say, but not all of it and I fully agree with you that nothing much is going to happen until it absolutely has to.
I also never said that every family should grow all their own food. I only said it was possible under the right circumstances. That's not practical in most cases these days with people living in cities.
My background is small-scale farming. My family worked the land for generations, and some of them still do. The long and the short of it is that if you have four acres of land and access to some extra grazing land, a few sheep and a cow, you can supply most of the needs of about eight people, including a few kids. If you also have access to fishing, that number goes up. When I was younger, we didn't grow all of our own food, just most of it. However, my parents' generation and the generations before them were pretty much self-sufficient and generated enough surplus that they could buy what they didn't grow themselves.
Yes, there are times of year when it is a full-time job, planting and harvesting especially, but for most of the rest of the year, on that scale, it's a few hours a week here and there, so it's perfectly feasible to have another job. In fact these days, with modern equipment, it's possible to get all of the planting done in a day and most of the harvesting can be done fairly quickly too.
The thing is, on that kind of scale, you're not going to be able to produce enough to feed more than your own family. If you want to scale it up to a commercial level, it gets more complicated, but it can be done. The biggest problems are apathy, complacency and resistance to change. It's far easier to order pellets of fertiliser and spread that than it is to spread manure. There's also a perception that modern, artificial means are better than old-fashioned, sustainable ways. However, you only have to compare soil samples from organic and intensive farms to see the how wrong that is.
You mentioned the pioneers. They faced a lot of problems, but a lot of it was down to the circumstances under which they arrived. Very little planning and advance preparation had been done. They had to clear land for cultivation, which, if you've ever prepared virgin soil, you'll know isn't easy. It's hard enough using modern equipment. They hadn't brought enough food to keep them going while they waited for their crops to mature and some of the crops they'd brought with them weren't really suited to the soil and climate they were trying to grow them in. Of course they were going to struggle. The thing is if they'd had modern farming equipment instead of horses and single ploughs life would have been much easier for them. A small tractor can do as much in an hour as a horse would do in a full day. How many acres can a combine harvester cover in a day? On average, a scythe team can harvest about an acre a day and then you've got all the threshing and winnowing to do afterwards. That's why farming used to be so labour-intensive. However, times have changed since then. Machinery does it faster so you don't need to have dozens of people working full-time to do the job. OK, harvesting some crops is very labour-intensive because they don't lend themselves to mechanisation, but, as you say, you've got plenty of migrant labour doing the work now, so what's the difference?
Modern farming could be much more environmentally-friendly with a few changes, but that's not going to happen immediately because it would involve investment, thought and planning, and would probably be more expensive initially, but time and market forces would bring the prices back down.