Afraid it might never fully die off. Human society is just too ingrained in religious clutches. Every time we thought it will die off it just rebounds back into the mainstream. But we still got to keep trying to spread truth and progress until it is no longer taken seriously.

In the UK within three more generations, (assuming civilisation survives) religion has less and less hold on the young fewer and few younger people are going to church or taking doctrine seriously (thank god, or rather don't) tolerance is becoming more socially acceptable.
Church attendance in the UK can be numbered in the very low millions and the majority of those are over sixty.
Only money is keeping the major institutions afloat.

More like a thousand years for religion generally to be marginalized into irrelevance. Perhaps a hundred years will do for Christian fundamentalism though.

Some religions are worse than others. Islam is by far the worst "religion" (in reality a political ideology).

Hmm sounds a lot like Socialism.

Sadly, as long as there are people who firmly believe in their religion, they will manage to pass it on to future generations. I would dearly love religions to cease to exist, but as long as there are unsure, tentative, and-or doubting (in their own strength and abilities) people, there will be religion to fill in those empty spots in so many lives. Religion offers comfort to people for myriad reasons. Not everyone WANTS to have a fact-filled life...

Sounds like any day in the life of human kind regardless of religion.

Religion will never relinquish it's hold on humanity.
Too many weak-minded people feel that they "need" it, and there will ALWAYS
be people more than willing to exploit that to their own advantage.
That is human nature.

I win I voted never.

Best guess would be a bit more than 500 years. Dumb people are breeding faster just like in the movie, Idiocracy.

I say 200 because by then we’ll all be dead and it won’t matter. But just in case I’m wrong then it’ll never go away.
It’s purely a creation of man in order to control the masses and to reap personal benefits.

So it might change its titles and messages but the intent will always be there because as humans we have a driving desire to dominate and fuck each other over by any means and at any given opportunity.

I would like to think we can change but I do not see humans as they are now letting go of religion until we can let go of fear of the other. Its a vicious loop. Even within this community you have people who profess hatred against all people of any religious creed in chosen ignorance of the fact that like all human constructs it is a sea of gray. That fear/hatred/rejection of the other; the person you do not know yet profess to know enough to hold in contempt, to hate. This is not unique to religion. We all have in our reptile brains a tendency towards it. It is a survival mechanism twisted in our hubris into a tool of horror. Hitler used it, Trump uses it, we teach it too our kids when we teach them stranger danger. And yes religions use it twist faith and hope into judgment and stupid anger. I think the better question is what can replace it for people who through lack of time/education or opportunity cling to it. I do not think Atheism can fill that void. Far too many humans want/need to be told what to do.