How did organized religion begin?

There's a great song from the '80's by XTC called 'Dear God' (it's been covered by Sarah McLachlan and others). It starts as a rant about humankind and how we've let the world go to pot. Then it changes course and becomes a rant at God - ending with the singer singing that he doesn't believe in God. In the chorus there's a line that has always struck me as very poignant - Did you make mankind after we made you? Interesting question, especially for a non-believer (like my brother the Atheist). Before I was a believer it's something I pondered quite often. When you look at all of the wacky religions out there that are clearly man made (Scientology comes to mind, along with any religion that asks you to cut off your own genitalia, kill your parents, eat garbage from a dumpster, live under the sea, etc), so many are easy to define as having a Deity that was created by the worshipers. But for the big 3 (Christianity, Judaism and Islam), how did they originate? Of course I believe that Christianity and Judaism are real in the sense that God communicated with man after creating the world. And I know the roots of Islam are in the old testament with Mohamed having a revelation from God. But somehow we all got organized and moved our beliefs forward, while Greeks and Romans, Norse and Egyptians all lost their faith... why? Why did these 3 take off? I know I'm leaving off Hinduism and a few others. But focusing on these 3 you've got 5000+ years of history - what the heck else has lasted some statically for 5000 years? It's almost a basic part of society. Doesn't that help (logically) with the relevance of Judeo-Christian beliefs? Surely if it was all made up people wouldn't be as passionate over the years to keep them alive and thriving. Whole empires have risen and fallen during the centuries, yet these 3 religions stay strong... it's interesting to me.