Is this projection based on current paradigms? Things could change rapidly at some point. I don't believe that the situation will necessarily move at a constant predictable rate.
You can see the current data (2017) on the above map. For Somalia currently some 75% people live in extreme poverty, meaning they earn less than $1.90 per day. But things will of course never be as projected. It could be better or even worse. For example for Ethiopia the extreme poverty rate is down from 66% to 22% in the last decades. It is not enough but it must not stay like this.
"The history of the past 30 years is the history of countries once considered hopeless cutting poverty and achieving historic growth: first China, then India, now Ethiopia."
"For example, Ethiopia, once the global poster child for famine, is projected to almost eliminate extreme poverty by 2050."