my little Prometheus theory

I think i got it The Engineers are a really old race, right? What about them being so old that there are just a few of them left, and that their plan from the whole beginning was to.. recreate their race? First they breed Life on Earth ( opening sequence ) Then they wait patiently that we emerge from the evolution process.. Maybe they passed by and readjusted things ( the dinosaur extinction) to give us a chance to take over the world they even payed us a visit from time to time ( wall paintings) to guide us on the path of evolution anyways... 2000 years ago humanity was ready, they where about to pay us a last visit and unleash a new forced evolution kick to recreate us again, and.. evolve up to their race standard... wich means the end of humanity as we see it .. we where just guinea pigs to start with, mere worms meant to reboot their own race, but because they missed the schedule, we where able to evolve our technology to a stage closer to them: creating spaceships and artificial life.. Looks like they didnt like it. your thoughts?