I'm not talking about merely holding a preference. I'm talking about hardcore brand loyalty as an outlet for people's natural religious enthusiasms. Ditto for political partisanship, activism, etc., where facts don't matter unless they reinforce one's preexisting belief. Just like religion.

Yes, I think they would regain their lost ground. In fact, given enough time, they might regain "all" of their lost ground.
Let's not forget that all religions were in a state of "black out" before their introduction to people since they didn't exist before. Then, when they were introduced, they gained ground and attracted millions of followers. In that regard, I expect a similar situation.

This is what would happen if there was no religion.

I understand that, but I don't really see the connection. Extreme supporters can be found everywhere, just as 'light' supporters can be found everywhere. Some people are extremely fanboyish towards their preferred systems while others don't feel the need to care about what others think or should think. Same thing goes for religion; some people try to push their religion down other peoples throats to a lesser or greater extend, while others are fine with letting others believe in whichever religion they may prefer.

Your comparison makes it sound like when people lose their faith, they start believing in consoles and brands and such to fill up the void. That would suggest that the greatest fans of a console are more religious than others - a comparison that I don't agree with.

If I misinterpreted something, feel free to fill me in.

Yeah, that seems like a rather sound argument. Keep in mind though that religion was partially used to answer questions that we couldn't answer at the time. A lot of those answers have been answered by science now, but it's true that the answers that we still don't have could make things start all over. We will never achieve complete knowledge, after all.

I'm saying that, if you're interpreting the decline of Christianity in western society as an indicator that we've evolved past our need for religion, we clearly haven't. When people are fat and happy and complacent, they are less desperate to exercise this need. But we are always just one cataclysm away from a religious revival. So, even if you were to successfully eradicate every existing religion, I don't see any reason why the old ones wouldn't eventually come back or new ones wouldn't arise in the post-oppression era.

I do think that you are too narrowly defining religion, but I don't think that hardcore fans are necessarily religious about their brand of choice. But if you were around here during the days of johnlucas and MikeB, you'd have seen that they certainly can be.

Problem with religion is that they offer "answers" to question that can't be scientifically proven.  No one knows what will happen when we die and we can't rely on personal testimony of people that have near death experience.  I actually had a near death experience in one of my dreams and I was floating above my body.  So there will always be religion until humans get over the fear of death.  Fear is the biggest ally of religion.

Yeah, exactly. The basis of it seems to be that we are terrified of ceasing to exist. But if there is something after this, then we will never really die.

I think this psychological trait is at play even in completely secular mass movements. Even if you pass away and are no more, you live on through the glorious revolution or whatever and so you didn't exist in vain.

The more interesting question I thought you were asking is: would any religion survive a resurrection of Jesus (as in, provably so). Assuming Jesus could make rulings on exactly how to be a Christian, would the "wrong" denominations with conflicting beliefs disappear? Would Islam disappear, given that it regards Jesus as A prophet but not THE prophet? Would unrelated religions disappear?

No it would not regain because people would just look at it as nonsense. Good OP, never really thought about that but I do believe it's true.