A few libraries in the Java world have this model. They haven't produced unicorns but seem to be pretty stable businesses - jOOQ(1), hibernate(2) etc. I'm researching DB libraries for work and so those are the ones I recalled immediately, but I think there are some commercial UI ones too.
I'm very happy that alternate universe doesn't exist. Libraries outnumber SaaS products 100 to 1 and I remember wrangling with software licenses on library implementations in the early 2000s. It sucked.
Distribution (the internet) and open source disrupted that business out of existence.
I think we need something like that for the cloud. Pay an interchangeable cloud provider a monthly pittance, and they host your choice of services as turnkey solutions. No more centralization of data, and no more paying $5/mo for a service wrapper around some FOSS CLI tool.
Why do you think it's limited to the FOSS world? Surely most SaaS companies (and certainly the most profitable) are business-to-business companies, and presumably they're quite a lot more valuable than the average library vendor. I would also hazard a guess that onprem services occupy an intermediate tier both in terms of profitability and in terms of integration model: they're a whole service (as opposed to a lib) but the customer is on the hook for integrating and operating (as opposed to SaaS).
> Only on the FOSS world, because it is the only way to force devs to pay.
What about the approach that the Qt library uses, where they have a free GPL version and a paid commercial license? People might pay to avoid GPL obligations while using the library.
The Qt Company recently changed their publishing model and they provide only recent versions as (L)GPL. Thus Open source users have to migrate to Qt 6 or run an outdated version of 5.7, missing bugfix releases. Migrating to Qt 6 however isn't easy as some components aren't available for Qt 6, yet. Thus Open Source users requiring those modules can't go anywhere.
Aside from that the Qt company restricted access to their builds behind a registration wall.
And if you are willing to pay they created a pricing model, which isn't easy to understand and can become quite expensive, (233$/month/developer) and as it's a subscription you can't simply pay a license and go from there, but you have to subscribe and the moment you terminate the agreement you are forbidden from distributing your application any further with Qt.
Thus unhappy open source users and many users who at least claim they would like to buy for sensible cost, but can't afford.
There is another alternative universe where commercial software, including libraries, gets sold
I remember old issues of Doctor Dobb’s Journal with full-page ads for libraries you could buy to add features to your shrink wrap desktop application. It was a viable business model once.
They certainly exist, but I don't think they are remotely as common. I can think of dozens of paid services that I use at work but one paid library. Maybe 5 if you include things like database SDKs where we paid for the database.
A lot of stuff in the automotive world has paid libraries. They can't be services because they need to be real-time, but they're not free because implementing a complex IEEE standard as software is not trivial.
There is another alternative universe where commercial software, including libraries, gets sold.