My theory: 

They are selling at $60 because it is worth less to consumers as a stand alone product thant it would have been bundled.  It will have less games than Kinect, and multiplayer games which use it won't be as fun if you are playing against people who do not have it.

I guarantee that had Sony bundled it in, they would have priced at 499.99.

You think they're taking a $40 loss on a peripheral? The original Kinect was a standalone product but it was still sold at a large profit.

Not being bundled, the eye obviously isn't a selling point for the PS4. The only reason it exists is as an extra source of revenue, just as the original PSeyes and Kinect were. Your "guarantee" is completely blind speculation.

It has to be, cannot think of any other reason. I do wonder though if MS is making a small profit and Sony a small loss, but i guess that still wouldnt make up for $100 difference.

@op - With regards to the 8GB. I suspect it might be slightly simpler than that. Perhaps they found out that MS were going with 8GB DDR3 and realised that even though their memory was faster that saying you have less memory is harder to explain to the masses. Also making both 8GB (even if there are differences) at least ensures developers have a similar memory amount to work with.

Nope. It's more than that.

PS4 is cheaper due to:
-Smaller, less complex motherboard
-No Kinect
-Smaller for factor due to better engineers

The less plastic/silicon/whatever you use, the more money you will save. 

Microsoft may have you believe that because their system is so complex and customized, it makes it the better system. They're wrong. The PS4 has an advantage here as their simple architecture is not only more developer friendly but also more powerful and easier to fully utilize.

Never said they were taking a $40 dollar loss.  Your inference that I said that is just blind speculation.

Same rationale applies to consoles being $100 more expensive for just a larger hard drive, or phone being $100 more expensive with extra flash memory.  Those products don't justify the increase in cost either, but they are the reason for it.

That's a lot of words to say one thing: Kinect.

It's because of Kinect 2.0. It's essentially a robot that turns on and off your Xbone, your TV, ties your shoes and orders you pizza and cheeseburgers.

These things don't come for cheap. It only does everything.

That prediction was made like 3 years ago.

Yeah it cost $50 to make and they sold it for $150.  I couldn't believe people would spend that much on a glorified eye toy...