Developed countries have something known as industrial agriculture (or farming) is used to raise large quantities of a crop.
Thanks to our consumerist culture, large quantities of a product are consumed and many times, in case of a food item, this places a massive demand on crop production.
This leads to a phenomenon known as industrial agriculture, where a farm is huge and only machines can harvest such quantities.
This is slowly happening in developing countries too.
This type of farming is leading to monoculture (a single crop), because farmers want to maximize their yield of a particular type and also there is an overhead for sorting, etc., and also the investment required is reduced because now a harvester for crop B is not required..
The problem with monoculture is that it promotes massive use of pesticides, and 1 pest or a disease can wreck the whole crop.
Also, farmers plant what’s good for their wallet, and not necessarily for you, the consumer and so you are forced to eat something that the industry forces you to.
Also, we would consume a lot of chemicals.
The flip side of this is polyculture, where there are small farms with a number of crops, which theoretically would use less pesticide because 1 crop’s pest might kill another crop’s pest.
This might be more natural and sustainable farming.
Also, monoculture could deplete soil and more fertilizer is required, whereas otherwise manure or other crops could fix the soil with nitrates.
As industrial farming increases, big corporations will buy out poor farmers, because the farmers do not have the capital required to invest in big machinery, big land, etc.
Unfortunately, this changes the landscape of agriculture.
This is not restricted to farming, and can also have political ramifications that lead to the farmers lose income and work and elect a populist government which promises to keep out corporations and immigrants, and also big corporations lobby the government.