I'm a grain farmer. Cluelessness in this thread much there is.
Here is a pretty good primer on malting barley from the
American Malting Barley Association.
At the end of the linked article, note the map which shows the states which grow most of the malting barley. Those aren't corn growing states. Corn subsidies? What the actual F? A lot malt barley is produced in southern Canada, right across the fence from the northern US barley producing states. The highest quality malt varieties tend to be produced in areas with a cooler, drier growing season, as opposed to the warmer, wetter conditions typical of the Corn Belt.
Some maltsters contract with growers to produce barley for that particular maltster. Some growers produce malting barley to sell into the open market, to any of a number of grain merchandising companies, which buy from producers and sell to exporters or domestic end users. The BMC brewers contract with growers to produce specific, often proprietary, varieties for the exclusive use of that company (here in Montana both MillerCoors and AB/InBev source much of their barley from growers along the east slopes of the Rocky Mountains, a region particularly well suited to malt production).
Malting barley is truly a specialty crop in comparison to the more widely grown crops such as corn, soybeans, or wheat. It's a more risky crop to grow because the quality standards are quite high and are affected by conditions beyond the grower's control. One rain shower just before harvest can create water stains on the kernels. If the grain is no longer pale, and was contracted for sale as pale, 2-row barley, the crop won't be accepted by the maltster. This results in grain which is suitable for livestock feed, but the price of feed barley is, currently, about half the price of malting barley, which isn't high enough to persuade me, and a lot of other producers, to grow it in the first place.
For some perspective-base malts can be bought, in bulk, from most of the usual online suspects for around $0.80/lb. The current price of malt barley, in Northern Montana, is about $0.08/lb. That’s a 10X markup from the farmer to the retailer. Of course, there's a lot of transportation costs at both end of the chain plus processing and packaging and two, or three, or four intermediaries (merchandiser, maltster, distributor and retailer) between the farmer and the brewhouse.
WRT the joys of growing malt, here’s another interesting factoid. Last year, AB/InBev cut the number of acres contracted in Montana by 25%. This year, the company is promoting the rice its beer. Coincidence? Yeah, must be.