That is the bottom line. The world is not a fair place and sadly might is right. This is how it goes. You fail to understand that concept and you will perish.
What drove Pakistan was the realization, blunt realization that we were alone against a enemy with nearly
seven times greater population. Now some will say numbers are not everything but what they ignore is numbers do mean everything. However tough guy I am if I ran into 7 guys or 20 women on both occasions chances are I would end up with the right beating even if I managed to knock few out.
To be sure, yes numbers can be defeated if you have technology at a level that is far superior to your enemies. For instance Israel. Clearly Israeli F-22 Raptors etc will prevail against Arabs despite their numerical superiority - although be noted that Arab superiority in numbers was always applied in a fragmented manner because it involving competeting Egypt, Lebanon, Syria, Jordan and Israeli's could knock each one out in turns.
Going back to India. It is composed of 30 plus states. Just one of those states, Utter Pradesh has population equal if not greater than Pakistan. Pakistan does have never had significant technological superiorty over India which means both are about equally matched thus in a fight it all boils down to numbers and resources.
In any extended war Pakistan would simply be bled white by the weight of Indian numbers. By early 1970s it was clear India was well on the way to developing nukes. Thus the historic decision made in 1973 to build a Pakistani nuclear device. What helped was ever since the British rule Pakistan had a small cream of extremely bright scientists. A good example of this was Dr Abdus Salam the Pakistan Nobel holder in Physics. He had pushed the then Ayub Khan government in 1960s to set up peaceful nuclear project and thus was born PAEC.
What really helped was Pakistan then was close ally of the West and under the 'Atoms for Peace' programme 100s bright Pakistani students were sent to USA and Europe to be taught on all aspects of nuclear engineering. DR Abdus Salam was cleverly laying the nursey seeds of a future talent poo. It was this 'pool' that Bhutto called on to come back and build the bomb. Rest is history.
The strategic result is Pakistan is now impervious to Indian or any other threat. Not even United States would take things that far. Thanks to Pakistan Army, Pakistan nukes it will never be the next Iraq, Syria or Libya. It is now estimated by some that Pakistan's nuclear stockpile is greater than UK.
The only thing missing in Pakistan's nuclear deterance is a nuke submarine fleet but we can be
sure within the next two decades the oceans of the world will have Pakistani nuke sharks on patrol.
Meantime let those who want to cry, cry. The fact that our nukes give some people heartburn tells us we got the boot right up where it should be.