One wonders what keeps Pakistan together

I wonder by looking at Pakistan and its history of last 60 odd years since its inception what keeps it together.It has a very dominant Punjabi(military)and culture.by the way i am Punjabi.which has not been very accepting to all others.Its arrogance and not accepting Bengali as equal became the cause of formation of Bangladesh.It has pleased different constituents by giving them autonomy almost to the level of state with in a state.
Some of the problems are the creation of the British . Like different family law for different constituents .It might have been expedient for a colonial power to do that ,but for a nation state not to have uniform family law is inviting disaster.Pakistan by declaring itself as Islamic state and now to implement sharia has complicated relations with in the country with minorities as well as modernity.
Sharia is negating the progress made by generations of women in Pakistan which made it possible for a woman to be prime minister.Modernity also allowed minorities to survive(except the Hindu's).A few Sikhs remaining are made to pay a tax to Taliban and for failing to pay many of their homes have been destroyed .It has shown the underbelly of Pakistan Govt,its law enforcement and institutions.Whole system is not only mute it seems impotent and helpless under the circumstances it finds itself in.