Nope.
It have more to do with socio-economical development of a country. There are "neat and tidy" places/developments in East Asia and South Asia, as well as not so "neat and tidy" aspects.
There is nothing "inherently" about it.
Correct. I've friends who are Indians living in Japan; they literally are practically Japanese. The way they eat, organize their house, almost no difference.
Environment shapes behavioral development. And I should say that it's wrong for people to generalize that South Asians are less "tidy" as I know plenty of Pakistanis, Indians who are very, very, very neat , tidy and organized. More so than I.