Why are Indian Parents So obsessed with marks and grades?

This is a very common scenario in most of the indian homes...

"Dad, i got my report card today. I got 90% aggregate" says a son to his father. Father looks at the report card and says " You are not putting in enough efforts son!! Every one is getting 90% these days. You should aim to get 100% marks in all subjects. Then only you can excel in life.. Otherwise you will just remain mediocre"

The son is clueless as to where he is going wrong. He keeps thinking that there is a fault within him due to which he isnt able to score good marks. He cant mention to his dad that this is all he can give and that there are other things in life rather than just cramming stuff from books.

Most parents quote instances from Gita such as " Put your efforts and forget about your results". But they screw the happiness of the child when he/she doesnt score expected marks.

Confidence they say is regenerative. If the child receives support from his parents irrespective of how he performs, he will feel more secure than a child who is always chided upon by his parents. Unless and otherwise this scenario changes, the child would never be able to take up any of his activities confidently.