This interests me as it has triggered a memory of an old 'fact' as told to me by a serious brewer a long time ago (20ish years ago).
I expressed to him an irritation that on a recent visit to the US (in 2003), my attempts to find local craft beer had resulted in finding craft beer stores which were almost entirely filled with IPAs, one of my least favourite styles. Brewer friend told me that IPAs were so popular in US craft beer because US malts had much less variety than we have here in UK/EU due to geographic and environmental reasons, that only a smaller range of grain would successfully grow there compared to here, so for a small brewery to 'stand out' from the competition, different malt bills didn't result in a big enough differentiation, while hops were king of variety, so craft breweries (at that time, 20ish years ago) ended up doing battle with IPAs.
I'm curious how much that has changed with time - science and agriculture advances are inevitable and this was a long time ago, so it wouldn't surprise me to learn that this is a solved problem now.