Thorn
I don't see how more technology would have any bad implications for any religion. If anything, the fact that "the gods left behind gifts for us" would actually probably help it. I suggest you stop making religion your scapegoat.
The ancient astronaut theories are interesting. It draws a lot of lines between many civilizations. I personally don't think these lines don't need to be drawn but it's still neat. All the evidence that these theorists gather up in support of the theory is pretty circumstantial as well.
I think I'm going to stick with Occam's Razor on this one and say that the simplest answer is probably the correct one; that these civilization's didn't need aliens to come about their (insert pyramids, Nazca lines, cave drawings etc here).
One of the only thing that supports the ancient aliens nonsense is the fact that technology to heave ten ton rocks to make pyramids simply did not exist in that era. Unless the techology was simply lost over time somebody or something definitely helped humans do some things.
Also, if aliens came and helped us build some cool shit, does it even matter if we have already surpassed, or are soon to surpass such technology?
If actual, rock hard evidence was discovered that showed aliens were being misinterpreted as being supernatural creatures then religious teachings would be bunk. This opens up another can of worms entirely, with religion having always had a large amount of power in ancient society, answering the questions of the scared and unintelligent and calming them etc, would it not be plausible to suggest that such evidence would be hidden or destroyed by such organisations that would be subsequently undermined?
It means they need to keep denying logic/reason/proof like they always have.
Thorn