Focusing on detail, blind to the glaring oversight

Rating: 6/10 (5 June 2012)

If you forget the characters (highly likely if you've seen the movie) and some of the stranger, slightly odd, superfluous goings on, you're left with a stunning, beautiful movie visually, but all I could think about was this...
Why go to such trouble to capture the detail of the Alien movie only to ignore the very thing that inspired this prequel. I'm not talking about the Xenomorph, I'm talking about the dead alien Dallas discovers sitting at the telescope/gun/controls in the original movie. When they discover him, they point out that something burst out of his chest. Sure, in Prometheus this happens, but he is not sat in at the controls on his own ship when it does.
I've heard some say that this isn't a prequel and even Scott has said that it just happens in the same universe. To me this doesn't stack up. They go to too much trouble to elude to its 'Alien' cousin which leads me to believe this was a prequel to Alien, but the oversight above made this unworkable. One simple amend could have changed this: the creator, having been face hugged, could have woken up made his way over to his -albeit damaged ship- to get a message to the other creators that the plan (whatever was going on with that) to destroy Earth went wrong. He could have died at the controls, thereby setting the Alien movie up.
I can't help but wonder, did they spend so long looking over the detail in the Alien/Aliens movies trying to make this the best prequel ever that in doing so they couldn't see the glaring oversight staring back at them?