"We all have our own set of ethical and moral guidelines, which are also lost once having been absorbed into the colossus. While existing licenses and agreements are imperfect, they have been shown to be enforceable in a court of law allowing me, the creator, power over my own creation."

This touches on the tension between artistic integrity vs. open source and the creative commons. There's been a shift from releasing software to benefit the public domain or "for the lulz" towards treating software more like a piece of artwork you as a creator have exclusive control over, even if it does have an open-source licence.

Sadly or not sadly, the freedom 0 in the four freedoms (freedom for any use) prohibits stuff like "anti-AI" licences, and even if it didn't, the mainstream argument is that you don't need a copyright licence because training upon a work doesn't constitute copying. Of course not everyone agrees with that, but once this is socially acceptable to say, it's also more acceptable to "more directly" copy existing projects, such as by directing LLMs to read the existing code and reimplement it, sometimes overtly, sometimes under the fig leaf of a "cleanroom" implementation.

Fundamentally, AI doesn't change anything if you wanted to do things the previous way - you can still publish your software, others can still use it, you can still forbid AI contributions or AI usage while interacting with your work - but it does surface the hidden implications. Many people do open source for the clout, for their portfolio and for approval from others, and those are things AI threatens, because it devalues software from requiring a huge amount of mechanical engineering skills to create to knowing how to prompt for good results. (see "without respect or credit for those who did the real labour.")

I wouldn't be so pessimistic about the new state of affairs - if creating software is much easier without the existing gatekeepers, a lot more cool things will be created :) People usually create things on their own even when not directly incentivised to do it with the power of law. In a way, this fulfills Stallman's dream - if you can easily modify or create any kind of software then he could have fixed his printer driver.

I really don't see how this would decrease openness, copyright itself decreases openness, and if everyone starts disregarding it then the field of software reverts to belonging to the shared commons.

I don't see why freedom for any use could not be 'freedom for any use except AI ingestion'. Copyright rests on control of your work product, customizing the license is definitely an option.