With respect, I suggest your experience is limited. I deploy embedded safety-critical software into establishments such as nuclear naval bases. We need tester

With respect, I suggest your experience is limited. I deploy embedded safety-critical software into establishments such as nuclear naval bases. We need testers because while the code works (we use formal and semi-formal software derivation techniques) there are, on occasion, unexpected interactions between features. You need to run through combinations of configurations and actions, and some of it can't be scripted because the interactions are unexpected - the Black Swan principle. Our cycle is a long one in part because acquisition programs in government and quasi-governmental organisations are like that. We can't deploy changes every day into the field. For one thing, we usually have access. For another, any change needs associated training and manuals. It would be a waste of a talented programmer to run through the sorts of detailed and exhaustive testing our software has to pass before it will be accepted. Perhaps you simply think that my company is placed in a less than ideal market. I assure you, it's worth being in the game.