> It's not like Americans don't occasionally need metric bolts.
It’s becoming a lot more common than not in fact. Automobile industry for example is pretty heavy on using metric bolts / screws. It’s not a recent thing either, a 2004 F-250 I used to have had many (most?) bolts as metric.
The US automotive industry started their metric push in the 1970s, and was mostly done in the 1980s for everything new. There are still a few parts from the 1960s and before that work just fine and so haven't been redesigned (and thus the bracket it goes on in a mix), but if there was ever need to redesign that part it would be all metric.
This only helps the tool makers. I wrench on Japanese and European cars yet every toolset comes with Metric and SAE sets. It seems to only inflate the parts count without giving you more functionality. The SAE and Metric bits are practically interchangeable.
> yet every toolset comes with Metric and SAE sets
I’ve mostly only seen that really with jumbo cheap quality “Father’s Day gift” type tool sets. If you are buying good quality tools, SAE and Metric are most often sold separately in my experience.
Why not go to the site and take a look. They, obviously, sell both metric and imperial bolts (and everything else).
It's not like Americans don't occasionally need metric bolts.