[homoeccentricus]

Many American sours are young and unblended, or if they are blended they are blended across vessels of the same age. It is rare to find American sours that have 2-4 year old components that are less sour or have a softer acidity. (Some exceptions would include NB La Folie and Cascade's sours.) So that is a big part of the profile of those beers. Lots of people here have a preference for the higher level of acidity so our brewers steer towards that preference.

Did you just say that La Folie has a softer acidity than most American sours? I didn't realize Warheads made beer. La Folie is one of the most tart sours I've ever had.

Extreme tart or sour does not bother me in the least. There are quite a few examples in Belgium, for instance Tilquin Oude Gueuze, or unblended lambics (e.g., from Timmermans). But that Prairie beer had some kind of in your face brett combined with the wrong type of hops that really repelled me.

EDIT: according to ratebeer, Prairie ale has saaz, ale yeast, wine yeast and brett.

[narvin]

I think the variation is large, like the craft beer industry itself.  There are some excellent American brett and sour beers... Allagash, Jolly Pumpkin, and Russian River really do them well.  On the other hand, there are a bunch of others that taste like a (dirty) kitchen sink... diacetyl, enteric, and other flavors from a "the more wild and uncontrolled, the better!" mentality. 

[reverseapachemaster]

Many American sours are young and unblended, or if they are blended they are blended across vessels of the same age. It is rare to find American sours that have 2-4 year old components that are less sour or have a softer acidity. (Some exceptions would include NB La Folie and Cascade's sours.) So that is a big part of the profile of those beers. Lots of people here have a preference for the higher level of acidity so our brewers steer towards that preference.

Did you just say that La Folie has a softer acidity than most American sours? I didn't realize Warheads made beer. La Folie is one of the most tart sours I've ever had.

Not the blend, just the older components.