Most creatures are, from a human frame of reference, extremely stupid.
A lot of creatures have very rudimentary brains, yet they survive and thrive. Even the dumbest human is smarter than most, if not all, other species. So what am I getting at? Well, it would seem that you don't need to be smart to survive. You could be a prosperous well-adjusted success story, and still be a total idiot. Idiots are proliferating because as long as they have what it takes to survive and thrive, then that's all that needs to be passed on to the next generation. Being able to drive a vehicle, use electricity, write letters to Santa, and utilise other's achievements to our advantage, does not make us as smart as the people who invented thMost humans are more like trained circus bears than autonomous homo-sapiens. So keep that in mind. Most humans are very good at something, but mostly stupid at everything else.