I believe that PCB is at fault here for not grooming players well and not helping them cultivate the winning mentality which effects them when they play in important matches. Furthermore if PCB can sort out their issue's then Pakistan can dominate all formats of cricket for a very long time, but in my personal opinion itll take few years before they can win matches/tournaments on the same level like Australia, England and team India do.
In subcontinent most of the boards are not having any well settled system which helps players, and they can do good for the long term most of the time we have issues of nepotism and personal like and dislikes which is surely killing merit and talent of the many youths even in many areas we have serious domestic issues which never allow having positive development for the progress of the game.
In recent years, we have few good changes in Pakistan domestic system but still it's never been easy to adopt them and have positive results from this all because political influence and many other aspects are creating mess up which never allowing to have strong system with merit and helpful for quality players to give their best just because of this when they are playing in SENA countries they never have confident mostly they play under pressure and lost games narrowly.
Pakistan has shown a great deal of improvement as compared to previous team , this recent team has revived Pakistan's name on international level as far as cricket is concerned. Current team under Babar Azam captaincy have won may matches series and qualified for many finals and definitely if they'll work hard and remain determined they will win World Cup final too.
Yes there is problem of nepotism and selection on basis of personal favours and this is present in all criteria boards .