I agree, but I think that says more about the market for OSes evolved with the assumption that the OS should provide core fonts "for free", as opposed to an indication of monopoly or lock-in.
The average person probably doesn't notice nor care about the small visual differences between major (OS-company supplied) fonts versus open-source equivalents.
I do.
And quite franky, all of them would laugh in your face if you told them that fonts are something that ought to be provided "for free". Fonts come from designers, designers work hard and should be paid for their work. Accordingly, real professional designers pay for fonts -- by the hundreds or thousands, sometimes, so many fonts their computers slow down if they don't use special software to manage them all.
This is also why the strongest, healthiest software ecosystem exists on macOS. Because macOS still has that cultural creative core of its user base, a culture which believes that people who create things should be paid for their efforts. Accordingly, you can still release a commercial proprietary program on macOS and expect to make significant money -- even from a small user base. That's certainly not true on Linux and it increasingly isn't true on Windows -- except, maybe, for gaming.
As for the average person, we're not even talking about the digital world. Everything in print, everything written on television, uses fonts. And if they employ professional designers, those are going to be commercial fonts. The real deal, the ones that were first set in hot type by Swiss or Austrian guys a hundred years ago or more. Open source substitutes are no substitute at all.
What do you mean by "strongest" and "healthiest"?
In my experience, most software is very cross-platform these days, and most platform-exclusive software is Windows-only.
That's a big *whoosh* or else you just felt like attacking a strawman.
Like I already said, I'm referring to how all major operating systems (including desktop Linux distros) bundle dozens of fonts to cover common needs. No average consumer is expected to spend additional money gaining the ability to see Greek math symbols or pseudo-handwriting or whatever.
It isn't the 1990s where you might see a retail-display box for Microsoft Windows 3.x adjacent to Microsoft TrueType Font Pack for Windows and Adobe Type Basics.
Similarly, disk-defragmentation tools are now in there "for free", and a TCP/IP stack is there "for free", etc.
Only platform that uses open-source typeface is Android with roboto/noto. If you are looking at webapps not marketing sites then yes you might get lot of Inter but trend is moving towards using system-ui font stack which is proprietary (except linux/android).
So no open-source typefaces are definitely not most used in practical use. Btw majority of the super popular ones are owned by Monotype the company this article is about.