I find it hard to believe that anyone thinks they know about the trajectory of the world's economies more than IMF, ADB, World Bank etc.
These medium term forecasts have proven to be extremely accurate in the past and unless something catastrophic happens then this is the way it will be.
Let us look at UK's CEBR prediction for 2035:
BD will have a GDP at current prices of 1.2 trillion US dollars
Pakistan will have a GDP of just 760 billion US dollars.
Remember by then Pakistan will have a population 2/3rds larger than BD but with a GDP around 2/3rds as big.
The two countries would then look totally different in terms of economic development - one solidly "middle income" and the other still 3rd world.