Ancient Aliens are just a plot device

In some round about way I'm thinking the Engineers in Prometheus will symbolically represent a potential evolutionary pitfall of man if he continues down the path of cold-hearted scientific progress at the expense of humanitarian values (such as compassion). In many ways Weyland Industries and specifically Weyland himself represent this attitude as it exists within our society today (and the near future) as corporate ambition/imperialism at the expense of such values (same theme is present in "Alien"). Subsequently its quite clear that a parallel is being drawn between Weyland Ind. and the Engineers (think terraforming) that is going to be the driving force behind this movie. This is why thematically it would be interesting to see Peter Weyland (if he is in fact still alive) mutate into an engineer as it would further illustrate this parallel between them. I don't think this movie is Ridley Scott trying to reinforce the case that Aliens spurred our evolution forward (though its quite clear that he believes something to this effect) but is instead intelligently using this as a plot device propelling the actual themes.