>I wish they simply measured clothing in centimeters, and all the complexity could be left behind.
Funny you should mention shoes, because this is exactly what european shoe sizes are. It's really just a case of, yet again, Americans stick with an ass-backwards system (inches/pounds/feet, fahrenheit, etc.) when the rest of the world has settled on something much more logical and reasonable.
Not really, Wikipedia says it is 2/3 cm +/- 2. Snatching defeat from the jaws of victory.
"European" shoes differ quite a lot between brands and even models in the same brand. A lot due to factories being slightly different and the materials used, but also in terms of how the shoe itself is designed. Size charts mostly only tell us one dimension (the length) of the shoe. If you're lucky you'll get width at one chosen point as well. Far from ideal.