> tech people [need] to build strong cultural expectations that people and companies who benefit from a commons should help keep it healthy
Agreed on this, but the "and companies" thing is a total red herring. Two things to note: even though you mention "people and companies", it's incredibly clear from popular sentiment that the conception held by most people of the problem/solution comes down to the latter (companies) and not the former (people). Focusing on companies at all—let alone allowing it to occupy a majority share of one's focus—is a huge mistake. Depersonalized abstract entities like companies are almost entirely immune to whatever methods of persuasion people have in mind here. Gay rights only just became kosher to "take a stand" on, and even then it's invariably limited to being trotted out as a vehicle for the most empty and self-serving marketing horseshit and other corporate speak that anyone should expect to come out of these institutions. Cultural pressure for open source by way of shaming companies doesn't stand a chance; it has to come down to people.
I've brought up the subject before: why do we rake companies over the coals for their inaction, but ignore the individuals? It's worth reflecting on the relationship between a company and its employees.
A company, no matter how many layers of management are involved, delegates some problem to an employee. That employee surveys the lay of the land and then elects to use some tech that is available from the commons towards solving the problem. In turn, they are rewarded by their employer in both tangibles and intangibles that are considered proportionate to the achievement and budgeted accordingly. Thus, that person is, in a very real way, converting the labor of others into personal gain—in the form of wealth, career prospects/advancement, and personal stature in wider society.
Why is it easy to frame a company as the perpetrator and hard to say anything about any given developer who benefited from this (and did not share)? Because it's uncomfortable, since it's too personal? That might make sense if we were talking about, say, a custodian with limited career prospects just doing their best to keep their head above water and provide for their family already, but that tends not to be the case where software development is involved. The implication here is clear. (Forget, for now, the prior argument I just made about effectiveness for a moment and feel free to focus just on the fairness aspect here, if it uncomplicates things.) If there's any appropriate allocation of social pressure to be meted out—resulting in social expectations to be met—then it needs to come in the form of beliefs like, "hey, if as part of your employment you are singlehandedly making something like twice the US national average of an entire household, and you're not giving away at _least_ 10% of your salary to the people who made that possible, then you're kind of a piece of shit." Is that a stand that people are willing to make, though?
It's acceptable to disagree with this, but to understand why you feel it's justified to defend the individuals involved means that you have everything you need to understand why there is no movement on the problem. Perennially and impotently opining that companies need to quit screwing around and do something already is a ridiculous strategy.