Ad supported search engines comes to mind, as one example: https://opensource.google/

/me dodges tomatoes

But maybe you meant something about software under the GNU license specifically?

I would flip everything around: At scale, doesn't a private enterprise run out of money to support large codebases?

This isn't a facetious suggestion. Every employer I've had in the industry has been drowning under their heavy codebases. They have massive amounts of vendored dependencies, and long tails of single-author modules. The bigger employers have to create special teams just for pruning codebases and cleaning up after old projects.

And they're losing the battles. Code sprawls between multiple cloud vendors. Services exist in ecosystems so large that they have echo chambers, network effects, and politics. New languages are slowly introduced and even more slowly removed, with most code being written in mid-level glue modules. Code ontology and navigation is primitive and limited to indexed search.

What makes FLOSS different? Political discussions have to bring technical justifications to the table, mostly; this is Linus' famous "talk is cheap, so show me the code" slogan. The openness of collaboration ensures that CI systems, code repositories, and other shared services are available to folks, although this is still a cultural situation that isn't quite uniform yet. (There's too many folks who only publish tarballs and don't share the rest of their infrastructure, which is fine but not very collaborative.)

The resulting ecosystem can directly and openly compare codebases, and deprecate code which is shown to be inferior or unsafe or otherwise undesirable. We have shown an ability to not just change code artifacts, but the protocols and languages which we use to communicate, at a very rapid rate.

Not really "large scale", but blender receives $122k a month from donations. [1]

If you ask me, donations are starting too look like a viable model for open source development.

[1] https://fund.blender.org/

> What sort of an economic model makes open source software feasible at large scale?

If you mean business model, pretty much any that isn't selling software licenses, particularly services around the software, whether SaaS or enterprise support. (And enterprise software, even when some of the payment is notionally license fees, is mostly about support, anyway.)

Non-profit (wikipedia, gnu, etc.) open sass or hosted solutions to open source software (wordpress, gitlab, etc.), selling hardware (System 76, Rasp PI, etc.) Entreprise support (Red hat and others)

Here is one we are making:

https://qbix.com/token

Specifically this part...

https://qbix.com/QBUX/whitepaper.html#Monetizing-Open-Source