FWIW, Budweiser is lousy rice beer. It doesn't even follow the Reinheitsgebot ...
Budweiser is an
excellent rice beer. Do not fool yourself; making beer that weakly flavored, (where it is hard to hide minor faults) and that is as
consistent as it is even though it is brewed in 12 breweries across the US with wildly varying water supplies, and with the kind of shelf life that it has, is no easy feat. From a brewing science standpoint, there are few (if any) breweries than can match up to Anheuser-Busch.
I do not happen to enjoy that type of beer as much as other beers with stronger, and more complex flavors, but a large segment of the world population (not just the US) does, as is evidenced by their global sales figures. It is not bad beer.
As for meeting Reinheitsgebot, that is not a gauge of beer quality. It is only an antiquated set of German brewing regulations, literally from from the middle ages, that limits the ingredients that you can use in making beer. You can make swill and have it meet those standards. Or, you can make fantastically delicious beer and because you used any ingredients besides those allowed (water, malted barley, hops, and yeast) it does not qualify.
The original laws did not even explicitly allow yeast (later ones do) because they were not even aware of its presence at that early time, and thought some sort of "magic" of spontaneous fermentation was taking place. Yeah, I'm sure that was some really tasty beer.