At this point I’m assuming most if not all of these content deals are essentially retroactive. They already scrapped the content and found it useful enough to try and secure future use, or at least exclude competitors.

Honestly? I'm down with that. And when the LLM's end up pricing themselves out of usefulness, we'll still have the fediverse version. Having free sites on the net with solid crowd-sourced information is never a bad thing even if other people pick up the data and use it.

It's when private sites like Duolingo and Reddit crowd source the information and then slowly crank down the free aspect that we have the problems.

The Ad sponsored web model is not viable forever.

I’d rather the harvesting be open to all than only the company hosting it.

Assuming the federated version allowed contributor-chosen licenses (similar to GitHub), any harvesting in violation of the license would be subject to legal action.

Contrast that with Stack Exchange, where I assume the terms dictated by Stack Exchange deprive contributors of recourse.

SO already was. Not even harvested as much as handed to them. Periodic data dumps and a general forced commitment to open information were a big part of the reason they won out over other sites that used to compete with them. SO most likely wouldn't have existed if Experts Exchange didn't paywall their entire site.

As with everything else, AI companies believe their training data operates under fair use, so they will discard the CC-SA-4.0 license requirements regardless of whether this deal exists. (And if a court ever finds it's not fair use, they are so many layers of fucked that this situation won't even register.)

But users and instances would be able to state that they do not want their content commercialized. On StackOverflow you have no control over that.