As a European if somebody tells me the diagonal size of a display in cm or meter, I'm simply not able to "grasp" it. I need to whip out the calculator and divide by 2.54, turning it into inches. It's just how monitors are measured in my head at this point.
When the Euro was introduced, I've heard people say things like "older generations will never adapt to the new currency, they'll always refer to the old denominations in their head" – which turned out to be completely untrue.
Adapting to new units is very possible, but it needs a concerted effort. Absent a good inherent reason or anybody capable of artificially creating one, it won't happen on its own.
Wasn't arguing otherwise. If anything, I was illustrating so: I used inch so much, that despite it not being the native unit of length measurement over here, for the specific purpose I used it for it managed to stick incredibly hard.
Using the diagonal to measure the size of a display is also a bit weird because it doesn't compare well across aspect ratios. A 34 inch 21:9 ultrawide is actually smaller (in terms of area) than a 32 inch 16:9 display.
