And more, smaller, robots vs large tractors could put an end to monocultures. Monoculture is the result of optimizing for minimal human labour, not an optimization for yields. So when labour is free, mixed fields are the way to maximize profits
But we don’t build computing like that any more. Instead of large centralized single devices we use a large amount of protean hardware with various adapts (software).
Hordes of small devices can flood through the fields, using sensors to decide at any point what to do, and can use different effectors for different tasks at different times of the year, like the humans used to do.
I mean an autonomous device that picks a row, then does the same on the next row on the way back, then maybe unloads into a hopper and continues with the next couple of rows. And you don’t one, you have 50 or a couple of hundred of them rather than one huge combine harvester.
And if you have 50 of these platforms designed to go up and down the rows they could have been doing the planting at the beginning of the season (or desuckering your vines in spring or whatever) using a different tool, so your capex isn’t tied up in a few huge single-application devices, but amortized over a whole season. And when you have a fleet, if one fails and needs maintenance it’s no more of a big deal than when one server in a datacenter fails.
Like these: https://en.wikipedia.org/wiki/Rice_transplanter https://sda-industries.com/equipment-parts/rice-harvester/
Compare that to "small" machines sold in the US. https://www.deere.com/en/harvesting/
Homogeneity helps with trading commodities, no question. And commodities reduce risk by allowing a very wide fan out on both sides of a two sided market…which has advantages and disadvantages for all participants.
More along your argument, it also lets the farmer use capital better in the short term (you buy the equipment you need for your monocrop).
But if you have multimodal devices you have the opportunity to take advantage of more flexibility. You can do crop rotation to use less chemicals or to take advantage of trends in the commodity market. You can have a different mix of crops for the same reason (half corn, half row crops, though they re typically worth less). You have more flexibility to adapt to climate change. The commodity markets can handle all this, in fact they help enable it.
This isn’t magic wand — crop rotation doesn’t make sense if, say, you have an orchard. But mechanization also caused us to abandon growing multiple crops in the same field, which can have benefits and improve yield. It was just way too labor intensive. If we go back to individual “labor” (automated in this case) it could be worthwhile.
Certainly the logistical challenge of multiple small harvests of varying products is there, but this is definitely more manageable with robots and computers than without.
And for a small close to population centers, if they can supply multiple kinds of produce reliably, they might be able to make orders of magnitude more money on the local market than on the commodities market.
As a result, we're still going to optimize for the most productive use of robots, just as we do for humans.