I like how everyone assumes that we are primitive if their are extraterrestrials out there. Who is to say that we are not the most advanced intelligent life there is currently, for all we know earth developed the capability to support life billions of years before any other planet. Also earth is a horrible example of a "life supporting" planet much of what is necessary for creating life is found in extremely minuscule amounts compared to what you think would be here. So for all we know there could be an advanced civilization on a planet that has only been able to support life for 1 billion years because of the fact it had a greater ability to support and nurture it. We can't really use our development as a basis for other life. A more stable planet that was hit by less asteroids and naturally contained the optimum amount of everything needed for creating life and allowing it to evolve and become intelligent then they could have surpassed us in a quarter of the time it took us to get where we are.

Also just for something to chew on, all early on significant growth in human technology is completely unexplainable, we seemed to periodically just jump ahead in our development, also we learned how to smelt gold before we learned who to do things that were much more simple.