Metrication will happen after Americans give up ICE vehicles like the Ford Expedition, ICE gestapo, ultraprocessed hamburgers, and climate change denial.
Metric is really far simpler, while Freedom Units are like going back to counting change in Roman-inspired £sd.
> Metric is really far simpler...
For the common, everyday use case it isn't meaningfully simpler, which is why the US hasn't switched. The conversions are certainly harder to memorize, but by the time you're an adult you have memorized all the common ones (12 inches to a foot, and so on) so that downside only applies to people who have to learn this stuff (largely children, who don't get a vote). The math is also harder than just moving decimal points, but when you carry a computer in your pocket that isn't actually making life harder for anyone.
So, the two big downsides of the imperial system (conversions are harder to learn and the math is harder) aren't actually a problem for the vast majority of adults in the US. But switching to metric would cause a ton of friction as you have to relearn how to estimate measurements for everything all over again. And those two factors combined are why the US doesn't switch. Most people will not gain any upside, while they have to pay significant downsides. It's perfectly rational to not switch when that is the case! You could argue that it's selfish (because future generations of kids have to learn the conversions, so they would benefit from metric and they don't incur the downside either), but it's not stupid. As much as people like to go "haha people in the US are so stupid for not switching to metric", that simply is not the case.
When I think about problems with Customary Units, I think not about decimality, but that the units are too disconnected. For example, there are BTUs and HPs that mean the same thing (power), but are wildly non-connected both to each other and to other units. While in SI, a Watt is Joule per second, a Joule is Newton times meter, a Newton is kilogram times meters per second squared, and voila, you have arrived at basic units. Your AC, your PC and your electric car have power consumption in the same units, and the same units are on your bill. This is what valuable, and not Greek prefixes.
And yet, many other countries have managed to transition to metric measurements without too much issue.
My parents were in their 30’s when Australia switched. They instinctively think in feet/inches, pounds for body weight (especially babies), but oddly miles hasn’t lasted.
I was educated in metric, but learned imperial lengths doing woodwork with my dad. I don’t have any intuition in pounds or miles, but feet (up to maybe 10) and inches are ok.
My son is purely metric. He can do the arithmetic, but has no intuitive sense in any imperial units.
So .. my anecdata is that it takes two generations to really switch.