LLM-first development is the future. If you don't like it then, yes, you should quit.
Obvious sarcasm aside, these LLMs have been trained (without consent!) on our hard work, on our passion. People have been writing code for years, and many have open-sourced their projects to share their knowledge, to better the world, to provide free solutions to problems. All that hard work, all that effort, has been stolen and used to create a machine that replaces us. And when we complain that quality goes down, that work is no longer enjoyable, that we don't actually see huge noticable productivity improvements across the board, bright minds like you tell us "lol just quit man fuck you". Do you not feel bad that you are actively destroying the livelihood of the very people that made your slop machine viable to build?
So then the question becomes what "copying" means. There is an extensive body of legal precedent on this matter, and it mostly all points to "transformative uses" being exempt from copyright. For example, if I count the number of words in Fahrenheit 451, that number is not copyrighted. If I reproduce just a sentence, or maybe even a paragraph, that also doesn't count. But at a certain threshold, once I've reproduced enough of the book verbatim, I have violated copyright. Training an LLM is also a transformative use which means that it is simply not covered by copyright.