OSS is diverse and there are many, obviously, who don’t mind not being paid directly.
But what’s confusing is that there are proprietary licenses. Anyone who doesn’t like volunteering time to OSS can write commercial software and charge for it. That’s the model that works for them.
But the talk of a 40 year old model not being sustainable is pretty funny. It’s more sustainable because it takes so much volunteer time.
It’s not the open-source model I called unsustainable, but a particular response to new forms of open-source monetization.
At any rate, the current model - of open-source as a mainstream R&D model, and as the critical infrastructure for the largest businesses in the world, primarily funded by corporate sponsorship and venture capital... that model is definitely not 40 years old.
You could argue that the model originated at the Linux hype of 1999, when Red Hat was the hottest IPO and IBM was spray-painting penguins on the sidewalks of San Francisco... Or you could argue it really started in 2004 when the Google IPO showed how much more scalable and profitable a business can be when you don’t pay software licenses.
In any case, the current model for open-source is really not that old, and it’s too early to tell how sustainable it really is.
When Stallman thought seriously about open source in the 1980s, it wasn't because he was the only one to ever imagine a culture of sharing around software and information. I think he was reacting to a sense that an existing culture was being erased by growing commercial interests.
One could also argue it originated with gentleman-scholars circulating letters about their new physical science discoveries during the renaissance and feeding into the subsequent industrial revolution. But, I expect it is an emergent property of humanity which is probably exhibited throughout history and pre-history.
It's essentially the same idea of commons and culture applied to yet another domain of knowledge and technology. Was it sustainable for the first farmer to teach his techniques to another? For one chef to teach another how to prepare his dishes? Open source software can be sustainable as long as there are needs and resources available to produce and execute software that does something different or better than could be done without the software (or at a lower cost than other available options). The subsequent sale of additional copies need not be a motivating factor at all.
That was not motivated at all by the open source movement. The only reason AT&T Bell Labs didn't charge a significant amount for UNIX is because they were under a consent decree which precluded them from entering other industries at the time, see https://arstechnica.com/tech-policy/2011/07/should-we-thank-...