Sure thing. In T20 runs are more important than wickets and you have to take some risky shots to increase your runrate.
The ups and downs in smaller teams are bound to happen when a generation of players retire. Sri Lanka went through that low phase and had got back to some extent. They are still not as strong as their legacy but are still better than many teams. Bangladesh and Pakistan are going through that phase. The stronger the local cricket infrastructure is, the quicker the recovery is. Teams like Bangladesh and Pakistan should regularly hold local leagues and hunt newer talents as you can expect a different things from a team that has failed multiple of times.
Pakistan is in the same phase as Bangladesh. However, if we compare Bangladesh and Pakistan, Pakistan is much ahead of Bangladesh and their spinners and pacers perform much better than Bangladesh. However, Sri Lanka went through a very bad situation in cricket a few years ago and Sri Lanka is slowly trying to overcome that situation and is also achieving success. But in the case of Bangladesh, such good players are not being produced and the good players are already retiring. If new talented faces are not produced, it is very natural that a cricket team will never do well in the future.