These are simply basic facts of the believers of the world. Few change their religious beliefs. In other words few seek outside their own belief systems they inherited.
Does not address your previous assertion. Considering the fact that many believe in conflicting diverse religions making the same claim you are making. Of course there maybe no God.
I think language causes a lot of confusion to do with religion. A person thinks their outlook is correct - otherwise he/ she wouldn't hold that outlook.
But we know that so many other outlooks exist. This causes problem: am I making a judgement on them being wrong? And, If most of us follow beliefs because parents etc., then how can one belief be correct if mostly luck decides who holds correct belief? So person says, all beliefs are narratives, but there is one truth. And organised religion is human invention, to help the human beings to the one transcendent truth, which is independent of religion.
The problem with this "solution" is even more problematic, however.
How?
Religion provides human being with a sure way of looking at the world. This is necessary for the human being to reach truth, that he begins from belief in truth.
Implicitly it cannot accept the truth of another religion; instead it respects whatever truth it contains and its adherents who follow that religion. But if he gives up the truth-claims of his unique outlook then he gives up the possibility of knowing truth, and he gives up faith and the possibility of knowing God. So everything would be lost.
We cannot know whether other religions are true, and can't say, we can only go from our own beliefs and what our religion teaches. This is a subtle difference but all important. Why? Because it goes again to the heart of what being in an organised religion provides, which is liberation from Knowing by the light of ourselves. I don't claim to
know the truth, I have a faith in religion which makes claims on the truth. Without the religion, then the individual is burdened again with passing their opinion on what is the truth, so placing themselves as the appointed Knower.
This is an attempt at saying why organised religion is vital and that relativisation of outlook risks throwing out the baby with the bathwater.
Islam teaches that all peoples have received revelations at different times, and that Islam itself is the primordial religion and not a new religion. It is possible to respect other religions, without needing to say that they are an equally valid pathway to truth.
Nearly every person has a religion as nearly every person is part of a people. It is just sometimes called by different names.
Just as person wants the water which flows from the natural source, every person wants religion which originates from pure non-human source. Even in secular society, people treat certain words with religious awe - they don't question - if you say because Equality demands it, people will be scared to object, and fall in line. The truth of this concept seems other-worldly in its power. Even though equality is manifestly neither an Absolute or in tune with human nature. (People seek advancement of their own self/group interest, and this won't end after pre-existing power structures are brought low.)