Absolutely. God could exist. But then he/she also could not. Because 90+% of the world believes in some god doesn't mean that god exists. e.g., the world is not flat because we all believe it to be.
Human beings in general have a need for explanations of the unknown. Human beings must also believe that there is some meaning in something. They also must feel purpose and they are also arrogant.
e.g., we are made in the image of god.
Religion provides a means for explanation anything that you may want to be explained. You may not like the explanation, but it always provides one. Even if its as simple as saying, "it was gods will".
But not everyone feels this way. Not everyone needs an explanation. And some things may not have an explanation but rather just...is.
e.g., maybe something doesn't have to have a beginning and an end. Why the search for the beginning of the universe? Maybe it was always just...there. This concept is too hard to swallow for most of us. therefore we explain it away but saying something created us...or there was a big bang.
These things are why I believe religion is a deeply personal relationship between a person and god. It is different for everyone. And the same can be said for those who want no relationship with god. They simply dont believe in god.
This leads to my last point. Religion as a personal relationship is what I believe religion was meant to be. It goes outside its boundaries when one person's views and religion is being forced upon another through laws that effect everyone. That is today problem. Evangelicals are trying to force feed their belief system on the rest of the world through common laws and through enforcement. I believe it simply goes against the idea of religion itself and hurts us all.