I think it goes beyond conservatism for most devs as to why you don't formally specify your design and its mostly rooted in why AGILE is so popular. The sooner

I think it goes beyond conservatism for most devs as to why you don't formally specify your design and its mostly rooted in why AGILE is so popular. The sooner you show a finished product, no matter how broken and incomplete, the sooner your client can realize all the things they didn't want they said they did and replace them. If you give them a formal design document it might be ironclad and foolproof but it doesn't put the finished product in their face to scrutinize. Money doesn't judge. It ends up in the hands of all manner of people. As programmers we want money for time, and the people with the money rarely have the education or willpower to even be able to comprehend a formal design. But they are the ones calling the shots with some esoteric vision locked up in their head we are meant to realize. As someone who dabbles in art too there are substantial parallels between the two. You sketch your piece and constantly refer back to your commissioner to verify this is what they want. Almost every single step of a painting or animation or music production or anything creative a commissioner will change their mind on it, either because you suggest something better or because they recognize flaws in their realized vision. Thats where "run fast and break things" even comes from. Making some piece of garbage "sketch" is way more informative to your average "commissioner" than having them write down to every intricate detail their vision for the finished piece. Because like with all other creation those we write code for rarely have the education to understand what they are even asking for. They have this nebulous idea of a fraction of a finished product and you need to basically teach them to see the whole picture along the way. Until they actually have even a remotely reasonable grasp on what they want all the testing, specs, design docs, etc are wasted because you still don't know what you are actually making. The more endemic problem would be that we still don't have an accurate way to convey the long term value in doing it right once we have a glued together rapidly iterated abomination that now needs to be redone properly. Thats where formal methods I feel have the most value - a developer can produce a formal spec for a near-finished product that, when they always fail to achieve the spec because the money stops when it "looks done" at least the next guy months or years later who inevitably has to pick up and fix this mess has a better idea of the intent than the person paying them would on the repeat attempt.