I don't disagree with your comment in general. But, just like everywhere else, ag is a very wide umbrella. There are niches which are ripe.
For instance, it is telling that you can drill deep into the earth, pump a liquid to the surface, process it, transport it a significant distance to an expensive port, pump it into giant floating tankers, sail those around the world, suck the payload back out and pipe it to additional processing plants, pipe it across a continent, refine it into relatively finished product, pipe it hundreds of more miles to a depot, pump it into tankers, transport it to underground tanks, then pump it back up to sell to customers. You can imagine how much a product would cost per gallon. Then, as a customer, walk inside to pay for the product you just pumped and snag a gallon of milk. Guess which gallon is more expensive?
Put the milk back on the shelf and drive to your neighbour's house. Walk around to the back porch where they sell their milk out of an old fridge. Um, no, they don't sell it. That would be illegal. They just happen to have a fridge full of milk that people keep stealing. But the thieves have a conscience. They keep stuffing money into the tin can next to the fridge.
Because in the U.S. it is legal to sell a product with a big label that says, "WARNING: THIS PRODUCT WILL KILL YOU." Unless that product is milk.
Plenty of people have figured out how to sell milk cheaper than gasoline. But they are restricted by regulation.
You may well agree with the protections those regulations provide. But it might also look to you like the same problem as taxi cartels.