Ahh, but that really is not true. According to W3 Linux OS share of web browsing is around 5.7% of the market total.
And according to NetMarketShare it's just 2.27% and StatCounter pegs it at a little over 1.5%.
Of course if you actually look at how the data you reference was collected:
From the statistics below (collected from W3Schools' log-files since 2003), you can read the long term trends of operating system usage.
We can see why the data seems to contradict all other sources, and why it pegs mobile use at ~5% which is obviously not representative of broader usage whatsoever.
This seems low until you consider that People do about half of their web browsing from work, and half at home, and the business world is almost 100% PC or Mac.
Neither of those things are supported by any evidence whatsoever, but more to the point your statistics are purely computers that visit the W3Schools website. The comparatively low mobile marketshare didn't tip you off that maybe these statistics weren't representative of the real world?
Taken in that context, that 5.7% ends up being closer to 12% when you consider just home computers that visit W3Schools website.
When taken in that context, Microsoft really only has about 75% market share on home PC's that visit W3Schools website.
This trend has been slowly moving for more than a decade, and there is no reason to expect it will not continue.
No it hasn't, according to all other reputable sources that isn't true at all. macOS marketshare has risen, Linux has not.