Why India is so famous in IT?

To remind you, India got Independence on the 15th of August 1947. I remember this date because next day (in 2017 not 1947) my son was born. India is very young country with main profits from agriculture, extracting and manufacturing industries. IT industry becomes famous in the 21st century. Mainly its IT outsourcing. Thousands of testers (they are the bulk and the less in the industry - are qualified senior level developers) , support engineers mainly in Bangalore, Chennai, Hyderabad, Mumbai have been working in International companies. So why India became so famous in IT? Several reasons like cheap human resources, high quantity of resources and globalisation = multimillion contracts. Recent years India is competing with Bangladesh in IT outsourcing. Along with low pricing from competitors Indian outsourcing like any outsourcing will compete with technologies, which focusing on automation.
Recent year, in my opinion, reality will push clients to integrate automation solutions. Less need will be in outsourcing companies. Many yesterday Testers will try to work as developers. To continue the logic chain - recruiters will be happy with developers and HRD won’t complain about her and developer’s difference in salary.