Raiders often have the education, know-how, and wherewithall of a ten year old. I chalk it up to tough childhoods and too much beer. If they can load their guns, it's a good day for them.
Well it seems like you're assuming that they were all born into it. You hear about people just quiting and joining and stuff throughout FO3. They have the ingenuity to rig up those pitching machine turrets along with plenty of other traps and hacking old security turret. You couple that with the fact that they apparently build their own armor and it seems pretty logical for some Raider leader (really tough Raider) to be able to mod some power armor. I'm not saying make it common but, you know like a bunch of chimps will eventually write Shakespeare, just in there from time to time. You never see raiders fighting each other either, insinuating that they seem to have some form of organization. (not saying they shouldn't fight, multiple tribes in NV??? EH EH???) Plus we all know that anyone that can't slap a mag in and [censored] the gun won't live long enough to meet other people, let alone build a following/spawn more retards.