Yep, though I don’t always squat that way, I often do. It depends on the situation.
Like TokyoBayer, I’ve lived in places with squat toilets for a loooong time, though western toilets have become the new norm in most places. Considering that I very rarely use squat toilets any more, it’s not the main reason I can squat that low. In my case, both martial arts and fitness training are important activities for me, so I’ve maintained a higher than average level of mobility. I can squat that low with heavy weights; doing it at body weight is extremely easy.
I consider the ability to do that type of squat a pretty good diagnostic of very basic strength, balance, and lower limb and hip mobility. If you can’t do an “asian” squat, it means there’s something wrong.
Older Japanese almost all spend time sitting on the floor, walking barefoot, walking a decent distance every day, and (sometimes, depending on the household) squatting to eliminate, which are all things that naturally promote at least a modicum of mobility. Now, Western-style furniture is much more common, so I see a lot of younger people who are less physically capable in some ways than their parents or even grandparents. It’s sad that there are so many adults — and I’ve even trained some teens in my after-school fitness program — who can’t do a full ass-to-the-ground squat.
High body weight is not probably much of a factor. It might be a secondary symptom of inactivity, but it’s not a root cause. There are sumô who can probably squat at least as deep, or deeper, than I can and the small guys are at least 1.5x my body weight.
Everyone, yes everyone, could do that when they were kids. I’ve never seen a kid under 5 or 6 who can’t squat. Hell, you could use a photograph of almost any random toddler as a training guide for proper squat form in a gym. You can lose the ability due to disuse, but you had it at some point. Stick a kid in chair behind a desk for 6+ hours a day, cut their PE and recess times, virtually eliminate unstructured outdoor play on uneven surfaces, and you get a bunch of people who can’t move. Go figure.