To be fair, people have been saying that for years, and slowly but surely, open source has been marching on. 10 years ago, no way, no how would Linux be even considered for desktop use. Now? A few people on this site have parents using it. Not there yet? Could be. It will be, though.
One of the signs of a 'not good enough' disruptive innovation is that the rate of improvement of the new thing is greater than existing tech. Windows and Mac were both fairly usable 10 years ago, Linux not so much (for 'ordinary folks' - I was happily using Linux as my primary environment at work in 1997). Linux has improved by leaps and bounds, and will continue to do so. Will it ever surpass MacOS? Maybe not, but will it hit a 'good enough' level? Certainly. It already has for many things. At the last company I worked at in Italy, full time, we had everyone on Linux, including the administrative assistants and call center people.
I think one reason Linux user interfaces have been catching up with Windows (if not Mac) is that for the past ten years or so, desktop-app usability has remained stagnant (or, in the case of MS Office, regressed).
Twenty years ago, Apple and Microsoft had to convince non-geek consumers that personal computers were worth buying, and so they had an incentive to make their products as usable as possible (given the constraints of cost and technology). Now that consumers see personal computers as things that they have to use whether they like it or not, there's not as much incentive to use the UI. Instead, people shell out their own money (or, if they're lucky, their employers' money) to take "how to use Microsoft Office" classes.
"Linux user interfaces have been catching up with Windows (if not Mac)" is a common misconception.
I love the tabbed file system views in Gnome. It's much more comfortable than the Finder. Windows Explorer too is simply terrible. I have been using Windows at work and Gnome at home and can't even begin to decribe all the ways Windows is completely broken from a usability standpoint. People tolerate it because they know nothing different and/or are unwilling to learn.
In many aspects, Gnome and KDE have already surpassed Windows and OSX.
One of the signs of a 'not good enough' disruptive innovation is that the rate of improvement of the new thing is greater than existing tech. Windows and Mac were both fairly usable 10 years ago, Linux not so much (for 'ordinary folks' - I was happily using Linux as my primary environment at work in 1997). Linux has improved by leaps and bounds, and will continue to do so. Will it ever surpass MacOS? Maybe not, but will it hit a 'good enough' level? Certainly. It already has for many things. At the last company I worked at in Italy, full time, we had everyone on Linux, including the administrative assistants and call center people.