Yeah! This usually happens. You can see the IITians get the salary range which is so high than other colleges in India. So these factor works due to the reason that in a competitive environment the student is competing as well as the reputation of the college ensures the quality of the education. So this fact occurs for 99% of cases there can be 1% of exceptions if a student from any other is competent to that of the IIT-ians.

I hope this answer helps. All the very best for your future endeavors!