Funnily, as a brit, I have always had the ability to sit in a deep squat comfortably and it's not even from tons of practice. I only even realised that its unusual to be able to do and that it may be good for you when I was about 21. By which point there were many people who couldn't do it already. I certainly hadn't been practicing it throughout my teenage years.
I'm a Brit who can squat too, and I think it has quite a bit to do with not weather shoes at home and wearing "barefoot" shoes / zero-drop trainers outside. I have a hunch that it's lengthened my calf muscles and achilles tendons, which makes squatting much more comfortable. I couldn't really do it before switching to barefoot shoes.
I have never worn shoes at home, that's for sure. Not into barefoot shoes though. I'm not really sure why it is for me. If it's to do with calf muscles, I guess we could attribute it that my mother never learned how to drive and so we used to walk EVERYWHERE. And we lived in a tiny town.
