This is one of the problems with IT: it has too little science behind it. A lot of things are built based on common sense, tradition, and chutzpah. Much like building was in medieval times. No wonder things often crash and take a hard-to-predict time to build.
Some things can be over-engineered but under-scienced, so to say, at the same time.
A lot of great computer science already exists, and is applicable, and some of it is taught at universities. But it's not required for a CRUD app or for a flappy bird clone. And when you grow up enough to want more complex things, a lot is already forgotten.
I have, I think, a different view: there is too much CS and not enough engineering in IT. The numerous CS grads have a bag of hammers as their toolset and so every engineering problem is a DS&A "nail." At least, here in the valley it seems that way. Outside of it there is at least in my experience much more of a nod toward software development as an engineering endeavor rather than as an exercise in pure CS.
Yes, the theoretic / scientific part does not percolate enough into the engineering practice. Thus the practice is starving without a good conceptual view, while CS may be lacking in engineering department and thus practicality.
Guess it really depends. Maybe the frontend landscape can be a bit more chaotic since JS started on really shaky grounds and so many new things come out all the time, but I'd say in general programming is still quite rigorous, especially if you're a big organization and can afford all the time and resources to apply all the best software engineering practices with a whole team. Even if not, modern developers generally do quite well. Actually, hasn't the problem people been complaining about centered on the presumed disconnection between CS academia and actual programming, about how a lot of graduates just simply can't code a simple task? I'd say a lot of theoretical CS is just not that easily applicable to actual engineering work. There's a reason why people divide science and engineering. The latter is so much more about ingenuity and practicality in a lot of senses. They're not the same thing and it would be really harsh to classify the whole field as some "medieval architecture" stuff. Not to mention there are still plenty of great works in medieval architecture!
Some things can be over-engineered but under-scienced, so to say, at the same time.
A lot of great computer science already exists, and is applicable, and some of it is taught at universities. But it's not required for a CRUD app or for a flappy bird clone. And when you grow up enough to want more complex things, a lot is already forgotten.