I cannot say for sure but if you look at the evolution of Hockey since the 1980’s when Pakistan and India were the powerhouses of the sport there have been many changes that these countries were (and are) slow to follow.
Call it arrogance, politics or whatever Pakistan Hockey .. and Cricket… have always been internally unstable. This flows down the “food chain”.
The political points seem to be an ever increasing instability within the organisation with power struggles going on constantly.
Arrogance comes in several forms like not being willing to adapt to the changes world wide in both training and tactics. Also too many former Olympians and National players have too much say in how the teams should be coached and managed..This may sound racist and probably is but I and several other coaches I know would not have former Pakistani or Indian representitive players in our teams because they were too unwilling to listen and be a part of our teams. There was also at times a lot of instability within teams for some reason. Sorry for that comment but this one comes from personal experience.
If you look at coaching and development, being a foreigner coaching sub Continental National teams and players is a poisoned chalice. The turnover of coaches is ridiculous. None really get the appropriate support and funding to be truely effective. Also behind the scenes there are always those who resent not being able to do it themselves.
Finally the style played relies too much on individual brilliance ( which has definitely always been a trait of sub Continental teams) where real teamwork from the coach and support staff down to the players is more evident elsewhere.
Finally not enough emphasis is placed on developing a sound progressive and innovative junior to senior development program. Whilst their National Under 21 teams perform well and Pakistan is still a force in Asian Hockey tournaments but struggle on the world stage, there is little evidence that younger players have really structured team oriented training.
I was at an Asian Hockey Tournament when Ric Charlesworth left the Indian National squad and went back to Australia. His treatment by the National body was diabolical and he was hamstrung from the very beginning. He did not say that because he is a good diplomat and fair minded but I got these details through observation and discussions with others.
My belief is that similar happens to the excellent quality coaches that have been through Pakistan over the last 30 years.
I am expecting a lot of down votes but look forward to the counter arguments to see how wrong I am as I am very willing to change my point of view because I miss the excitement of Pakistan (and India ) in full flight.