Iowa is pretty rural. ;-p
Yes, but Iowa is a rural section of a first world country, while India and China are still more like third world countries despite developing fast.
I have read that there is a vast difference between the modernized cities of India and large parts of the countryside where rural villagers live lifestyles that are in many respects decades less advanced than the city lifestyle. And I think there is also a big difference between Chinese cities and the Chinese countryside.
If, and that is a big if, there is a similarly vast city/country divide in India, China, and nearby countries in the alternate universe of Star Trek at the time of the Eugenics Wars, and if the big cities in India, China and other Asian countries are destroyed in the wars, the surviving rural populations might be much less interested in, or qualified for, colonizing other planets or joining Starfleet and so might be underrepresented in Star Trek.
And of course Riverside, Iowa, may be far more cosmopolitan a few centuries in the future when Kirk is growing up there than it is now.