I know other factors influenced the American Craft Beer/Microbrewery trends of the late 70s onwards, like the legalization of homebrewing under Carter in ’79, the popularization of cask and traditional ales from Belgium and Germany and the success of Anchor Brewing Co in 1965, and the USDA/Oregon State trials in releasing new hop varietals like Cascade and Williamette that were more flavoursome, but
a) why the gravitation towards British heritage beer styles when German brewing had strongly influenced the American Brewing industry since the 1860s,
b) Why such a focus on IPAs, pales and stouts (to a lesser extent porters) and ignoring other styles like bitters, milds, golden ales among others?