Honestly the fault can be blamed on the fonding fathers of the state I think. Look how painfully the American fathers planned it all out to ensure there would be no king or military take overs. They consulted greek works, islamic works, roman works, gathering the knowledge from all sides to combine the best of all governance systems. Say what you want, but the US does have somewhat a functioning democracy. Our founding fathers didnt have a vision and made no safeguards. Even the empires of antiquity had reforms that spanned and held the nation together for centuries.
That is after 200+ years of existence as a country with countless wars, a massive civil war which killed 600,000 Americans, apartheid, civil rights and god knows how many other evolutions.
We are a relatively young nation with a significant portion of our population that is uneducated and unable to understand its own rights and fight for them within the confines of our constitution. Unlike Americans, we are divided into countless ethnicities, clans, tribes and sub-cultures with the only thing holding us together is religion. As such, Pakistan was a miracle when it came into existence and it is a miracle to this day as dysfunctional as it is.
We cannot compare ourselves to even East Pakistanis because they are one ethnic group. It is challenging enough for them to stick together but certainly a lot easier than the menagerie that we have cobbled up in Pakistan.