“In my experience developers are very rational beings.”
Yeah, no. Stopped there. Vanity is rationalizing the belief that you’re any better at being rational than the rest of us inchoate apes.
There are many technical, logistical, and political arguments as to why improvement (in any sphere) is hard, but if you’re not going to start with “It’s Us, The People” then where usefully are you going to start?