How do OSS devs support themselves without money?

Usually they are supported by donations, therefore they don't need to sell their user's data or their software.

The same way you can make model trains and not make money.

The Stardew Valley gambit - quit programming and take up subsistence farming.

Good luck. Farming is a hard business if you want to make money. And you'll need money for electricity, fuel, medicine, etc.

I have an employer who pays me to do thing X. And they don’t care that I also work on thing Y a little bit.

I think there’s lots of software written by people who have jobs and code because it’s fun.

For example, Linus Torvalds made Subsurface [0] as open source. He had a job while he made this. He didn’t get paid for it directly, but it’s not like paying him extra would make it better.

[0] https://subsurface-divelog.org/

Maximising profits and being sustainable are 2 different things. Museums do not need to make money because they are funded externally. It is like saying artists do not need to make money. You seem to go to the very extremes.

I'm certainly in favor of free software projects making enough money to be sustainable.

It could be zero in some conditions, but in the other cases, I'm also against ads. Fortunately, there are other ways of making money, without compromising the "open source" / "free software" part:

- consulting (including prioritizing new features and fixes)

- support

- providing an actual paid service

- selling free software extensions (and yes, that means someone can recompile the extension and distribute it gratis - that's what happening with OSMAnd+ on F-Droid, but they are still doing fine)

Museums do get money from somewhere.

Where do you get them for web?

Same place as museums. Benefactors.

Check out Wikipedia for an example of a huge site that doesn’t make money and just runs on donations.

I run my crappy blog and a bunch of other sites for “free” because I just pay the fees.