I have two Xbox One controllers that have developed such bad analog stick drift that they're unusable, and I know other people (IRL, not random folks I Googled) who have the same problem.
I also have a PS4 controller that completely stopped working because it fell four feet onto a carpet.
Given how many dead controllers I've seen without even any baby to blame, I'm not sure the Steam Controller necessarily that much worse.
That's incredibly bad luck. I've currently got 2 dualshock 4 controllers (the launch ones with the known fault of the dodgy analog grip), anxbox 360 controller and an Xbox one controller that are used regularly. (Xbox one controller used in work for ~4 hours a day maybe?) and the only issue aside from the known DS4 fault is that my Xbox 360 cable needed the removable connector replaced.
Mind you, I don't regularly drop my controllers from 4ft (1.3m) either, so I can't comment on that.
I also have a PS4 controller that completely stopped working because it fell four feet onto a carpet.
Given how many dead controllers I've seen without even any baby to blame, I'm not sure the Steam Controller necessarily that much worse.