MAYBE ENGINEERS WERE NEVER INTENTIONALLY CREATORS

I don't know if anyone's asked this question already, but maybe Dr. Shaw was wrong all along. That the engineers originally came here not to create but to clear off all life forms so that they could inhabit it in the future because they discovered their sun will one day go nova. Perhaps in the opening scene, what we all assume is an act of creation was actually an engineer poisoning the planet to kill off its dominant life form--this being during the Jurassic period. And we were just an unintended accidental byproduct of this. When millions of years later they discovered the planet is now full of a new species, they intended to repeat the original mission--that's why they want to kill us. Has anyone thought this is possible?