Imagine if the Founders of religions found themselves before God on Judgement Day and the following conversation resulted:
Founder: I stand before you, ready to receive my reward for faithful service to you!
God: Depart from me, accursed one, into the eternal fire that has been prepared for the Devil and his angels.
Founder: WHAT?! How can this be? What about the revelations you sent me to establish your faith on Earth?!
God: You are an IDIOT! I never sent you ANY revelations, nor did I send any to any other human! NO ONE that is a mere human can communicate my Word to others! That was a lie of Satan. It was Satan who sent you those phony revelations, and being the egomaniac you were, you passed them on to your followers. The result was incredible suffering on Earth, which you must now answer for!
Founder: But how was I supposed to know the revelations were of Satan?
God: By using the mind I gave you. You failed to do so. So did most of your followers. They will be condemned too.
I know, it seems incredibly unlikely. But no more unlikely than assuming that there is indeed one true religion founded by divine revelation while all the others that also claim divine revelation as their source are false. So what if there IS no true religion anywhere? Does that mean there is no God? Not necessarily. There may be such a God and even such a Judgement Day for all humans to give an account of themselves before Him. But we will never know our fate until that day.