A simple out of the box solution is intercropping. The loss of a single crop in a multi-crop system is not a ruinous loss compared to monocropping. It also reduces the requirements for pesticides and fertilizers if done well.

Yep. See Sepp Holzer's mountain farm for an egregious example of this.

I'm not a native speaker, but generally "egregious" means "particularly bad", is that what you meant?

Is this solution compatible with contemporary mechanized agriculture ? Seeding, spraying, harvesting by machines ?

Otherwise, it's like finding an automobile manufacturing improvement that can only be used with hand assembly. Besides Rolls-Royce, it won't help anyone.

Yes, depending on the particular intercrop. It's an area that could benefit from the application of robotics.

Somewhat, but 180 bushels of corn at $3.50/bushel is worth more than 60 bushels soybeans at $10/bushel. Farmers only grow soybeans because they are a source of fertilizer for their corn and so it works out in the long run.

This is why farmers spend so much money on insurance.