Atheism is unstoppable.

[Mister Agenda]

You can believe whatever you want, but people who actually study this stuff for a living have come to a different conclusion.

Correct, but based solely on religious trends. We don't know how to factor in things like the modernization of Africa or the impact of climate change or new technology, the predictions just assume that religious belief will hold steady and increase as fast as their population does, but religion isn't an inheritable genetic trait, there's no guarantee the next generation of Africans will be as religious as the last one. America was highly religious, and the decline has been relatively sudden and only obvious in retrospect. For instance, the Millenials are the first generation to become less religious as they grow older, that's a reversal of a long-standing trend. And that won't necessarily be true of the next generation after it. Our powers of prediction aren't up to it.

I don't believe religion is ever going away, but the next 40 years are probably going to surprise us in many ways, underestimating the increase of atheism may be one of them. Or not. There's certainly no basis for faithful adherence to either view. Certainly the absolute number of religious people in the world is going to continue to increase faster than the absolute number of atheists in the short run.