Phillysun -
You are correct about they buyer beware aspect.
All too often, things are bought based on price without any regard to standards or quality and the person ultimately living in the residence is stuck with it because they did not care either. The U.S. standards and testing are woefully weak, but the knowledge and interest shown by distributors, retailers, and contractors is even worse.
The problem lies with the importer, distributor and retailer for only being driven by low costs and quick availability. After the 2005 hurricanes (Katrina, Rita and Wilma), the importers of cheap Chinese drywall (and other products) were able to get the products quicker to the market than the American suppliers because everyone (especially contractors) was interested in availability and being able to supply drywall.
I think the correct name of the manufacturer is "Knauf Tianjin" (possible Herman or at least a German name). Tianjin is a major area with a population in the area well more than most U.S. cities.
There is very good drywall in China, but the junk probably goes to the price availability, sensitive markets through importers because they can respond quickly and the and be cheap for the products that may not be able to be sold in China. Walmart ships from China on mega-freighters that are too big for any canal and can cut 4 days off delivery times with only a crew of 13 people (plus cooks and maintenance). - the world is shrinking and few people appreciate the perspective. I had several trips to China before I even saw a "rick-shaw", but I quickly recognized the Mercedes and BMWs out-sold Buicks, but Buick supposedly sell more cars in China than the U.S.
China is a vast country with most population centered in cities along the coast and along rivers. TRaffis to bad because of the number of big cars in old cities. One example is when i went to Kun Ming (about 5,000,000 people and about 19th largest in China and called the "Spring City" and home bases of the "Flying Tigers"), where the housing complexes were about 2-4 blocks by 4 blocks with playgrounds separated from the 7 to 20 story buildings by community areas, recreation centers and swimming pools.
Very little construction in China is drywall and wood frame because the government finally has discovered it is not ecologically sound for them. There is still drywall used in the many 20-60 story commercial buildings since the walls will eventually be changed.
It is just a matter of cost and availability and no regard for specifications in the U.S. If you allow people to dump on you and are not competitive, they just get the junk.