Atheism, in it's many forms, today, will look as ridiculous as the really, really, old religions of yesteryear. We aren't much closer to explaining anything than the Mayans or the Native Americans, who were going on the best science and philosophy of their time
Highlighted the problem with that statement.
Maybe there's something that can show the Hardline Atheists that denial of something that can or can't be proven in the first place is silly, and that attitude be excised from the populous (or everyone starts to be more rational and unilaterally decides that's not their position, where they even considered it). Or maybe something about the Universe is found that actually brings those in the "not even considering a God" camp to align themselves as total deniers. And that's just covering a two of the myriad of flavours.
A doubt all forms of atheism will be excised, much the same as all degrees and specific sub-types of religion are. In fact, I doubt that while there are sufficient populations themselves brought up within a given religion (or other world-view) to produce offspring who will themselves sufficiently retain their parents' religion (or world-view) that any religion will die off. Mutations/evolutions, yes (and, of course, the occasional side-stepping to another type and hybridisation/sub-selection of multiple beliefs, as environmental/social effects act upon us, as long as worlwide communications and travel allow youngsters to fall under the influence of non-parental/motherland systems of thought and interpretation) but only complete and utter extinction if/when a some latter-day (self-?)proclaimed Messiah or Guru or Leader (wishing no prejudice, by that label, as to any particular denomination in this example) takes all of the followers off to a single island in the Pacific that ends up being wiped out by Tsunami or other disaster.
Also discounting any particular state-enforced creed (including strict and/or non-considering forms of Atheism, such as a certain nation of note has considered) actually having the double-whammy of taking over the entire world (by military, economic or other means),
and somehow develop thought-crime control mechanisms to be applied to suppress even covert worship/philosophising of all other forms of thought. No, I don't see that.
I predict that we will end up with
more forms of atheism, and theisms, and encompassing all the rest of the philosophical viewpoints. Filling the gaps. (Indeed, another use for the term "God Of The Gaps", I suppose...) Especially if interplanatary (and then interstellar) colonisation gets off of the ground. Plenty of 'island habitats' that can develop new considerations. And (unfortunately) more opportunity for diametrically opposed (or even diamatrically similar, but differing only in magnitude) opinions that can consider each other so Wrong that the resulting war is more than a War On Words. But maybe that's too pessimistic an end-game...