Naw.........ya'll have it wrong.
The stone circles were set up to mark the party zone. This civilization lived long before mass transportation and roads were set up. Therefore, you couldn't very well invite neighboring towns the the bachelor party on Friday night being held at Zimbob's Tavern, corner of 4th & Lee - so they set up the stone circles and sent smoke signals to the invite - something like "party....here...in 2 moons.......climb big hill......find large stones....bring beer"
Also - the circle worked as a sort of "barrier" - keeping those party animals in one area. Without the zonal area the drunken ancients could have wondered off into the desert never to be seen again. This way they could all be safely found by their significant other companions come morning when they had passed out next to the head rock. Additionally, there was no smoking allowed outside of the tribal party zone area - this protected the young innocent ones from smoke.
See..............we really haven't changed much in 5000 years