To be completely honest as someone who loves craft beer, homebrews, and hopes to open up a brewery of my own one day, ABInbev is a brewery operations wonder of the world. Yes, they use a ton of rice as one of their fermentables which cuts down on calories, alcohol, body, etc., but that's sort of what the american light lager has evolved into anyway. The real amazing thing about ABInbev is how they have production breweries across the world making the same beers and no matter where you are they taste exactly the same. They sell in the hundreds of millions of barrels annually while the best small breweries that have recently expanded rapidly and are battling with quality control (Trillium and Tree House are the 2 that come to mind) still only sell tens of thousands of barrels annually.
Beer aside, ABInbev is the definition of an evil company. The beer industry is known for being a community more than a competitive industry. Craft breweries collaborate with their "competitors" all the time. Even in close quarters such as Brooklyn/Queens, Other Half, Interboro, Transmitter, LIC Beer Project, Threes, Grimm, and Evil Twin are collaborating on beers with each other every other month or so. It's one of the reasons why I love the industry so much. ABInbev does pretty much the opposite. Sure, Goose Island still collaborates with breweries as a subsidy of ABInbev, but as a company ABInbev offers incentives to bars/bottle shops/wholesalers/distributors that require them to only carry ABInbev owned products or a certain percent of their products.
For example [1]:
> Under the new incentive plan, AB InBev refunds 75 percent of this money if its beers make up 98 percent of the distributor’s sales, according to documents provided to lawmakers by AB InBev.
Even with these incentives, craft beer is slowly taking market share away from ABInbev and they're are starting to feel it (although they still have something like a 40% market share so it's not that huge of a blow). I can't speak for other beer conglomerates (SABMillerCoors, Heineken, etc.) and if they try and give similar incentives, but I know for a fact that ABInbev is trying to kill any competition in an industry where everyone is rooting for their "competitors" to succeed.
The Reinheitsgebot is no longer in effect. Using rice as a fermentable in your beer doesn't make it any less beer than adding adjuncts like chocolate, coffee, fruit, vegetables, etc. While I can certainly appreciate the history of beer in Germany and the rest of Europe, there's a reason why there a bunch of breweries in Europe that are trying to emulate new styles that American breweries are creating. And most of them involve adding adjuncts. Milkshake IPAs include lactose and usually some sort of fruit. NE IPAs involve using flaked wheat or oats as a large percentage of the mash.
Yea, it's funny how they had to add yeast after they realized it was the reason why beer is beer. But I agree that barley, water, hops, and yeast are the ingredients needed to be called a beer, but beer wouldn't be as great if brewers weren't allowed to experiment with a bunch of different adjuncts.
The beer that "tastes great" and is also "inexpensive" usually cuts corners in one of the above areas