A few software markets have been completely dominated by FLOSS: system software, compilers, lexers, shells, kernels, codecs, programming languages, arduino-like tools...
On the professional market, just look at what blender became. Other examples for end users: OBS is probably the most used broadcast software available. People ignore that most people don't need the features Sound Forge and Audacity has probably many more users. Other examples in this same category: VLC, Handbrake, Inkscape, 7-zip, Calibre, Krita...
Even on the places where it is not a leader, it is sometimes good enough. I can totally easily edit a video using kdenlive; record, edit and master a music using Audour; compose a scene using Natron; compose music using MuseScore; edit 3d models using Wings3D; design an environment using SweetHome3D; render using many of the top-notch state-of-art FLOSS renders like Luxrender or whatever comes with Blender these days.
Desktop software is much more beautiful, intuitive and stable than before. And it doesn't try to milk you for money, attention or personal data. Flatpaks, AppImages and snaps finally make it possible for users of the most popular distros to use the same software, the same version, working the same way regardless of the distro.
Now, go back a few years. The situation was entirely different. You could do nothing of what was described using only FLOSS if you go back enough. Or, you could, but it would be complicated and unstable. This is no longer the case.
Of course there are still gaps, but many have been closed over the years and most remaining ones are slowly closing.
While not discounting how good coreutils are, everything you've listed is basically a commodity at this point.
Companies who live higher in the stack swoop in and claim all of the value.
It's a gradual release of intellectual property into the commons, similar to the expiration of patents and copyrights, but at a pace determined by market forces instead of government regulation.
You're right that "Good Enough" takes many forms, and it is a moving target. But whether it's closing the gap might just be a difference in which timescale one uses.
Today I can wipe the entire drive on my MacBook and re-install everything from scratch over the internet, without install media, directly from the firmware. When can I buy an off-the-shelf computer that can do this with Linux ?
After installing macOS I set up my account, enter my iCloud details and all my photo's just appear, I can send and receive text messages, phone and video calls. My clipboard syncs to my phone, and I use my phone to take a photo or scan a document and insert it directly into whatever document I was typing. I can start typing an e-mail on my phone, decide it's too long to type on the little on-screen keyboard and seamlessly move the task to my desktop. I can take a photo of some text on my phone, copy it as plain text, and then paste the text into anything on my desktop.
All of this with no setup required.
How much time will it take Linux to be able to do all of this ? And what else will it have to catch up to by then ?
The problem is ‘good enough’ is a moving target and FOSS isn’t exactly closing the gap.