Ridley: Says prequel will explore where the 'space jockey' came from and then maybe even where those aliens came from
He has never mentioned them being created by the SJ's, that theory was made up by fans using their imagination, ridley i would say knows this so would want to do something different, if he's going to blow the lid on were the jockeys come from, them maybe he wants to keep the aliens origins a mystery, for now at least.