India has a lot of Engineering students.
There are around 60k students joining Tier 1 colleges every year in India (IITs, NITs, etc funded by the Central Government alongside some private colleges like BITS). Very few students from Tier 1 colleges join these consultancy companies. Most of them studying CS from these colleges join product companies like Flipkart, Swiggy, Paytm, Amazon, Microsoft, Uber etc.
Consultancy companies get students mostly from 2nd and 3rd tier (mostly private) colleges. Pretty much all these colleges are in a very bad shape. I think there are over half a million students enrolled in these colleges every year. Students still go to these engineering colleges since the education is not as expensive as in the USA and it's what pretty much everyone do after high school. If it was USA they would have just left college altogether instead of wasting money on a terrible college.
Sure, the quality of education of Tier 1 colleges can be improved a lot as well. But generalizing the entire Indian engineering education as the reason why these consultancy companies are doing poor is not correct either.