I'm not American (and don't live in the US), but this is a ridiculous over-generalisation. The US is a massive country of over 320 million. It attracts architects and designers from around the world, as well as producing many influential and world-leading figures of it's own. The country is so vast, that making such sweeping generalisations like this can never capture the enormous quality and scope of design (good and bad) that must stretch from one side of the country to another.