People often do write things because they learned a common approach at a previous job or because they saw such an approach when reading someone else’s code. People are often hired specifically because they have experience in a certain area from a previous employer, so are dointhe same sort of thing at a higher level.

We fought this battle over a couple of decades with remix culture (“you stole that line/beat out of my song!”) and the world is better because the over-clingers lost.

There is no shortage of reasons not to like copilot, but I don’t consider this one of them.

Sometimes people do, and in any case copyright isn't limited to just verbatim copies. You can't, for example, reuse characters or plots from other works of fiction in your own novel, even if you rewrite it in your own words: https://en.m.wikipedia.org/wiki/Copyright_protection_for_fic...