In 2014-15, I did a rough calculation of salaries based primarily on Indian government inflation figures. What I found was that 12k USD inflated adjusted was same as 5k USD in 2007.

Today, 5 years later, this figure is surely even more inflated. But if you talk to graduate engineers from these companies they still pay 5k USD. So, I don't know if we can safely say there is no exploitation here.

The counter point obviously here is that there is a large young population joining the workforce each year. So, ensuring everyone gets an IT job as well as paid well is a challenge.