It's impossible to ban religion everywhere in the world. It's in the first amendment of the American Constitution. Even put a little ban on a little bit of religion in America, and people freak out. It would be immediately brought to the Supreme Court and deemed unconstitutional. The only way for religion to be banned in America is if the first amendment is edited or repealed entirely. And the only way America will allow that to happen is if the vast majority of Americans really want religion to be banned, and vote in Congressmen who also want to ban religion. Most of America is religious, and would not do that, though atheism is on a slight rise, it would take centuries for enough Americans to become atheist, and even longer for them to want to ban religion.
I feel that if religion will be gone, than it will just grow out of fashion, like nearly everything else in human history. But banning religion will cause more problems than solutions. Mass rioting, armed violence, general chaos. Now, not in every country will that happen. I'm just giving extreme examples. But banning religion can cause more violence than religion itself has. I say just let it die out, if it will.