This is the curse of Home Depot, which doesn't stock much, if any, metric. I was recently in a Home Depot where an Asian woman was trying to get some fasteners to repair some piece of metric restaurant equipment, and wasn't aware how backwards the US is on metric standardization.

The US needs to go hard metric. That means metric fasteners and components. The rest of the world does not have inch tools. This hurts exports. The 95% of the population that can't use any tool beyond a screwdriver can still talk of inches and miles, but physical stuff needs to go metric. Autos, aircraft, and DoD switched decades ago. It's mainly building components that are still inch.

In the US it probably makes more sense to go with an inch-based standard, since it's easier to find materials in those sizes. I've been making up my own 'standard' for rack-mount electronics with an eye towards making it work nicely with as many other defacto standards as possible (19" racks, standard lumber sizes, pegboard, unistrut, erector sets): http://www.nuke24.net/docs/2018/TOGRack.html

You can just buy the closest match and cut off a bit of the end. In the end it's much better for everyone to standardize on the superior units

Indeed. Which is why I standardized on inches, which match the hardware at Home Depot and whose rulers make it easy to divide by powers of 2. :P

Aw shucks. Downvoted for disagreeing with the HN groupthink.

First rule of HN groupthink is don't acknowledge HN groupthink. Just downvote anyone who's different.