Good quality domestic craft beer and imports are typically very easy to find in most populated areas in the US in my experience. Granted I'm in a big city (Chicago) but the "big box" liquor store here has a whole aisle of Belgian imports, for example.

That said, a quick googling shows that 2/3 of the American beer market is still dominated by non-craft domestics (AKA your cheap, watery lagers like Bud/Miller). Even amongst the craft segment it's definitely the case as another commenter pointed out that IPAs are overrepresented for whatever reason.

I think where we're still really lagging behind is quality of beers at your average bar. If you know where to go you can find great selection but the average bar probably still has just a handful of decent non-domestic-lager offerings, likely in cans/bottles. In comparison to when I lived in the UK and it seemed like any corner pub would have a couple great draft ales .. it's not the same.

The perception from the UK is despite what seems like a growing trend in microbreweries, Americans still don't venture out much further than IPAs

Edit: And as a lover of belgian beers I can only agree. I wonder why people even drink so many IPAs when there's so many different and delicious varieties of beers around.

Because the easiest way to sell a crappy beer in the US is to dump a bunch of hops in it and call it an IPA? I jest there are 47 varieties of Pale Ale and 3 of something else at the supermarket these days, but it's not far from the truth.