If you want things, you get them written into the contract. that's how business works. Eg the license for Facebook's llama model says if you have a ton of users you gotta pay up. if this were something small, like maybe give us a shout-out once in a while then hey, but we're talking substantial actual resources that shouldn't be left to implied assumptions. because if you don't actually talk about it, what I assume and what you assume is reasonable is going to be on different planets.

A license can allow something, but there can still be companies that are good citizens of the open source community of things licensed that way and other companies that are not so good.

In turn, that can affect how likely others are to view those companies favorably and/or cooperate with them.

e.g. I favor Prusa 3d printers over other vendors because Prusa provides substantial resources to development of the tooling that we all use. Other vendors are (usually) compliant with the contract, but may not be seen as good citizens by everyone in the community, and this can have consequences even if it doesn't have legal force.

In my opinion this is completely backwards. You should reserve all of the rights you intend to exercise. This is indeed what most companies have always done; you don't go randomly giving people copyright licenses to e.g. your characters and then get mad when they use them. Instead you just tacitly allow some unlicensed usage of your IP. That really is a social contract that exists in different places across the world.

I understand that some people didn't always understand the consequences of their choices, or maybe wrongly thought we all agreed on these unwritten social contracts, but we don't agree at all and I hope the lesson is learned well.

None of my prior work contracts stipulated not to microwave fish in the break room, or how often I ought to shower; some rules have to stay unwritten (or be in vague clauses), otherwise every contract will be tens of thousands of pages long.

Look, you can argue about the existence of social norms till the cows come home, it won't change the fact that there is a non-trivial subset of open source developers and users that believe the lack of discrimination of any kind is exactly the point of Open Source. The definition is not stipulating these rights indiscriminately by accident, and it did not have to be written that way. I will acknowledge that some people in the community clearly believe that enforcing unwritten social rules with regards to Open Source is the best practice, but I don't accept that this is the common or obvious viewpoint. I think that viewpoint is overrepresented in spaces like Hacker News with a lot of startup-adjacent folks but even here I wouldn't expect the majority of people to agree with this.

P.S.: This all having been said, while I think that there aren't commonly-shared unwritten rules w.r.t. who may do what with open source software pertaining to its copyright license(s), I don't think there's absolutely no "unwritten rules" in open source. For example, I think the CLA rug-pull pattern is a pretty dirty trick, but that has little to do with open source licenses and more to do with outright deceiving people. And even then, it does beg the question of why you would agree to sign something that explicitly grants that right when there is absolutely no reason to do so.

In the context of free software the entire ethos is complete, unabated freedom to do anything except restrict freedoms.

Even that wasn’t free enough for some. Permissive licensing allows you redistribute software without even disclosing your patches.

These are radically different to regular contracts.

Sure; and I don't see how this adjusts my point. I support the freedom that the license also supports.

But there's plenty of things people can do with freedom that bring consequences; they just don't bring legal consequences.