However I don't understand where did they work all those years?
One of the main concern is that people do not understand the code anymore. Without any snark - the word "anymore" does not apply here. People did not understood what they are doing for decades now. Random copy-pasta from stackoverflow anyone?
Another concern is slop. I once untangled 1500 lines algorithm that turned to be a simple DFS. "Programmer" simply did not know what is DFS, copy pasted several pieces with random changes. Tell me about LLM slop.
One thing that changed is scale - now the same people who did not care have the 1000x power to produce bs. It's not LLM that tells engineers to push thing they don't understand. It's the people who care less about that code. They did not care previously, they do not care now, they will never care...
I'm a bit bitter here because I thought with LLMs we will be able to do more "right" things. Because it's essentially free now! If you care - LLM will teach you the right thing. But majority do not. And that's the problem - not LLM.
Why majority do not care is a separate topic of leadership, after all why a reasonable human would not care?