It took almost 10 years to bangladesh to prove that they are of some value, after they got test status.
But if you see Afghanistan they are doing very well (that is not reflecting if you see the points table)
We also have to Consider that this is the first time that they are playing in England (most probably) that too in WC, where they had to face best XI of every side who are playing cricket since decades now.
England can be a tricky place even for a good & experience batsman. So, we can not expect Afghanistan batsman to do magically well.
I can hopefully say that in coming few years Afghanistan will make a big improvement if they continue their progress.