I would counter bet that:
i) I do know quite some of the constraints (though surely not all).
ii) Quite of these these constraints are self-imposed prisons that the respective company/industry created for itself because of historical or "political" reasons.
What you call "constraints" is something that I would rather call "the industry's preferred flavor". Well, I do have a different taste than the respective industry. :-)
Believe me: In the past, when I was frustrated of my job, I made use of an opportunity to present some ideas that I had to some former friend who has been working in business consulting for many years: he really told me that some my ideas could be as impactful for the respective industries as I imagine it, but they would be insanely hard to sell (and a huge part of his job is selling things to customers) because they so different.
To give an even different perspective: at my current emplyer's Christmas party, my boss' boss said that I am the kind of person who cannot be classified on an optimist-pessimist scale, since I don't behave like an optimist or pessimist, but rather like an statistical outlier in a data set. :-)
I would bet my entire salary you only believe this because you don't understand the constraints. When I was in my 20's and thought I knew everything I had the same attitude. I have since gained seniorship and worked in regulated industries and it's much clearer to me now. People in the industries you're talking about are generally smart and well meaning, but the constraints imposed by things like regulation and legacy systems (internal and external) make things that seem like they should be easy really hard.