You are speaking from personal experience or you get it from some source? Provide something which would help me learn.
Both, but I have travelled to remote parts of that region and I am a pathan myself. We are friendly and a have a greater sense of brotherhood and hospitality towards eachother but Pak pashtuns are generations ahead compared to our Afghan brothers. That country has been in war for almost 4 decades. No schools, no jobs, no basic facilities. Give me one reason why Pak pashtuns would reunite under such conditions?
Try to befriend youth on fb, interact and learn.
Can't exactly blame Afghanistan for that mess. They were/are weak and victims of geo-politics.
The biggest problem is lack of unity. Three largest ethnic groups, the Pashtun, Tajik and Hazara can't stad each other.