A statistical point to mention: almost everything follows either bell curves or exponential curves. (Bear with me, point is coming). Our data on when sapient life developed in the universe (or a subset thereof that's larger than our solar system) is limited to a single data point (ours). Therefore, if we assume the statistics on development of sapience follow a normal distribution/bell curve, then it is most probable that exactly 50% of nonhuman sapients developed before us (actually, any distribution you choose would have to assume that when given only a single data point). Exponential would mean there are some alien sapients out there who have been around an extremely long time.
Thus, it is most probable that, assuming there are nonhuman sapients among the stars, then a significant percentage of them are more developed than us (and, let's face it, our development was far from streamlined - the dark ages, for one), or at least, have had more time to develop than us (not the same thing; society around 300 CE and 1300 CE in Italy, for instance).
Also, while Earth appears to be much more rich in resources to other planets (and earth-sized moons in the outer solar system), we really have no way of comparing the resources of another planet capable of developing sapient life. And even within the solar system, Mars is the only other planet we've done any kind of in-depth material analysis, and that's been going on for about a decade and drawing from small samples taken from surface material, as opposed to Earth having seen thousands of years of mineralogical analysis (with varying degrees of sophistication, of course), including material several kilometers deep. Our other resources, including fossil fuels (except methane), wood, and all types of food are not found on other planets in our solar system at all since all of them are derived from biological processes (or, in the case of coal and oil, processes acting on the remains of biological stuff.
And while greater understanding brings reduction in wars (at least in our case - see next paragraph), it wouldn't breed ignorance about the whole idea of the possibility of needing to defend oneself against aggressors, merely restraint from actually using such weaponry unless it was necessary (comparable to the Cold War, but hopefully a little more civil).
The US people complain about Iraq's casualties being in the thousands, while that would be considered minimal casualties back in the late 1800s), despite the fact that the weapons back then were large, cumbersome cannons and a near total lack of rapid fire weaponry. (The Gattling cannon was one of the first machine gun type firearms developed, and that was only in the 1860s (ish - the American Civil War))
Sorry for the rambling response: short form, we have no reason to assume that other sapient life forms are universally less developed than we are, hence we assume that some are more developed. (If we assume they exist at all, but we're not talking about Drake's Formula, are we?)