I am afraid.
We always had some exciting talent. Our young players are always at the same level with other test playing countries. But when they reach the top level somehow they tend to fail.
A partial reason may be lack of good coaching and infrastructure. Another reason may be our typical Bangali mentality. They don't think about reaching the international standard. As long as they can keep their place in the national team they seem to be quite happy with it!!
And Allah Knows the best