I think that if there were no "religions," that is to say superstitious organizations designed to appeal to the innate nature of humans to believe, that would indicate that "belief" is something that isn't hard-wired in our brains and DNA.
If that were the case, we also wouldn't have superstitions, UFO nutters, believers in telekinesis/psi powers, astrology, tarot cards, a fear of ghosts, etc, etc.
There are those that will use the circular reasoning of religious texts to ethnocentrically and religiocentrically support that theirs' is the "true" religion, but this, too, is a part of the hard-wired system of belief, and merely reflects the believer's desire to be right in his/her beliefs.
There are those that criticize this hard-wiring as a flaw (Bill Mahr calls religion "neurological disorder!"), but I think it's a characteristic that can be either deleterious or helpful, depending upon the level to which the individual applies his/her belief. Overall, religions of the world have a positive side, which is to reinforce values and morality that are common sense to humanity and independent of religion. But to the extreme, religions can impose variations of morality that exclude those that do not subscribe to that religion's set of superstitions, rituals, and cult activity, but to those of another religion altogether (as in Islam v. Christianity; Christianity v. Native American religion).
Religions can even apply extremes and variations of value and morality upon members within the cult. This could be to legitimize hierarchy, gain wealth, preserve fundamental beliefs, prevent progressive changes, etc. These actions can even exist because of misinterpretation of the cult's belief structure. Good examples of each of these includes the Inquisition, the Reformation, stoning adulterers, disallowing priests to marry, sacrificing virgins in cenotes, bloodletting, etc.
But without this hard-wired belief, would humanity have progressed to the extent that it has? Could science exist without the innate system of belief that its greatest innovators must have felt about the nature of the universe? Would agriculture have emerged unless early Nartufians believed that the Earth was the womb of life and that seeds of wheat were the equivalent of the Seed of something like "Father Sky?" Would complexity have emerged in larger populations unless there were those in the population that believed that some were better or of a higher status than the rest?
There are perhaps a million other questions that arise relating to the hard-wired nature of belief in humanity. There are many reasons to point out that his is a flaw in the Homo sapiens brain, but there are probably just as many reasons why this can be called our greatest characteristic. Undoubtedly, those that haven't tempered their belief-module (I don't actually think there's an actual, specific part of the brain that is responsible for belief, but rather a system of parts, based on what little I've read on this so far) with critical thinking that will call what I'm saying baloney, bunk, etc. It may very well be. But it provides a ready explanation, in my opinion, for some very curious things about humanity.
So, back to the question of "what if there were no religions?" I think if there were so, then that would imply that there were no belief-engine or module within the human brain and, therefore, we might be intelligent but unmoved technologically. There are those that say dolphins are intelligent.... could it be that they simply aren't afflicted with religion?