I'll try to keep this a little more brief than the sprawling mess I spit out on Monday about "descriptive" versus "prescriptive" interpretations of style. But, I think the Oktoberfest "style" is a pretty good example of Americans getting it wrong and the over-reliance on style as a prescriptive ideal.
If you'll recall, last year the Beer Talk Today guys and Madison Beer Review teamed up to taste a number of "Oktoberfest" style beers. You can listen to Part 1 here and Part 2 here. One of the interesting things to come out of that 13 beer tasting was how similar a number of the beers were and how very different others of them were. And, contrary to the staidness implied by my missive of the German brewing industry we saw that it was the Germans, not the Americans, that were most divergent from "style".
How can that be? Think about it for a second. It is a style that is, in theory, based entirely on a limited subset of beer. There's not even a "universe" of beer to describe. There are six breweries at the Munich Oktoberfest. Technically, these are the only six breweries in the world that are even allowed to call their beer "Oktoberfest". For the interested, those breweries are: Paulaner, Spaten, Augustiner, Hacker-Pschorr, Lowenbrau, and Hofbrau.
Yet, the BJCP describes "Oktoberfest": "Domestic German versions tend to be golden, like a strong Pils-dominated Helles. Export German versions are typically orange-amber in color, and have a distinctive toasty malt character. German beer tax law limits the OG of the style at 14P since it is a vollbier, although American versions can be stronger. 'Fest' type beers are special occasion beers that are usually stronger than their everyday counterparts."
The description is rather interesting. You'll note that it highlights the American hijacking of the style. Indeed, one of the things that we found in our tasting was that the range across the four German Festbiers was far broader than the remaining nine American. The Germans were everything from light and distinct (Weihenstephaner) to rich and Malty (Spaten) to hoppy (Paulaner) to a pale and light-bodied (Hacker-Pschorr). Three of these four comprise half of the only breweries in the world even at "Oktoberfest". I can tell you from experience that Augstiner's "fest" is similar to the Hacker-Pschorr, if a little maltier - though no darker in color.
Yet, the American version is almost invariably amber-colored, medium-bodied, and rich; often with some caramel notes and sometimes very hoppy. Heck, Avery makes an Imperial Oktoberfest. Yet, the American's always invoke "German tradition" in marketing these beers. In turn, Americans tend to think of Oktoberfest as a rich, malty, amber-hued beverage and thus, we come to expect it. Since we expect it, breweries make their Oktoberfests in this fashion - no one is going to mess with "German tradition" so the beers tend be uniformly similar. The final turn of the screw is when the BJCP and Brewers Association "describes" the style that has developed and publishes the findings which breweries and consumers take as a prescriptive notion of how the style should be brewed.
To be fair, thankfully both the BJCP and Brewers Association note the American stylistic differences from the German. The BA goes so far as to separate the American from the German entirely (though still calls them "oktoberfest", not simply "festbier"). Yet, inexplicably, American advertising of these beers calls up the German heritage and history and implies, if not outright absconds with, connection to these Bavarian brews.
It is through this iterative narrowing focus of the style that the marketplace becomes "boring." Boring here isn't a derogatory term, it just means that the style is uniform with little to differentiate the brewery. And, it's all based on this idea of prescriptive reading of style - whether in hard-line form from the guideline authors, or from consumer expectation.