You forget that if you live and work in US, your cost of living is also the same as any native. 1/15th would only be attractive to person in India at Indian prices.
Besides, why would someone take 1/15th, if they can have the whole thing? I mean, by a similar logic, you'd expect people in US readily undercut each other at 1/2th, 1/4th etc in a race to the bottom. But we don't.
People in the US have to support a family at US living standards. Indians on the other hand either have their family in India or are used to living in conditions that Americans balk at, multiple people per room, no lawn, one car or less per family.
Listening to the dumps some of my co workers live in I can see why median hourly wages have not increased in the last 40 years.
This is political economy 101. One of Malthus's suggestions for reducing the mortality rate was getting exotic materials to become staples of life so food wouldn't be the limiting factor of population.
Besides, why would someone take 1/15th, if they can have the whole thing? I mean, by a similar logic, you'd expect people in US readily undercut each other at 1/2th, 1/4th etc in a race to the bottom. But we don't.