Why so many West Asian but so few East/South Asian countries?

I'm pretty ignorant about world soccer/football in general (I'm Australian and mostly follow AFL, if anyone knows it), but I'm wondering: there are so many Middle Eastern countries, even like Jordan, along with other small nations like Cape Verde, Curacao, yet so few from Asia. I have heard Asia is a tough group, but it seems the only East/Southeast/South Asian nations that qualify are Japan and Korea, and Australia and sometimes NZ as they're technically part of the Asia federation. ​ Are other...