That may be true, but generally speaking, if you look around US cities you'll see far fewer mixed use zones that blend commercial & residential. Besides major metros (cities with actual skyscrapers) and small towns, in my experience it is not common for cities to allow (or perhaps they do allow it, but it isn't encouraged or developers don't believe it makes sense) mixing of residential units in commercial blocks. I'm reasonably well traveled in the US and never noticed this until I went to New Orleans for spring break one year. That was the first city where I saw mixed use like this, and it actually confused me when I was looking for businesses and they ended up being interspersed between houses.
Generally speaking the US does not mix single-family residences (1-4 units) with commercial. However with multi-family residences (> 4 units) mixed use is the norm.
The driving force is the fact that most single family homes are owner occupied, while multi-family housing is not (that is to say, while condos and coops may be owned, the building itself is not)
Whoops, you're right. I should have said 'Based on my experience of working in NYC, America has the most restrictive regs...' US States have about the same power over regulations as individual European countries have in the EU.