He specifically didn't say that. Instead of criticizing that they aren't nuanced enough you should read the nuance they actually wrote:

Let me be clear: The odds of a massive, immediate shift away from Windows PCs aren’t great. This isn’t a “year of the Linux desktop” rallying cry. But if there is a Linux desktop that exists today, it’s the Steam Deck. And that makes SteamOS a bellwether for greater proliferation of non-Windows devices (if not necessarily “Linux” specifically) in a huge range of form factors.

I don't know how long it'll take desktop Linux to reach 10% market share. Could be a couple of years, could be decades, could be never. But once it reaches 10%, I give it 5 years before it's over 80%.

It's the year of the Linux Desktop!!

Well, there are a lot of newb-friendly distros these days. Some options:

• Linux Mint (any spin) - one of the easiest to get help with online, with minimal compromises
• Fedora - also pretty easy to get help w/ online
• Bazzite - great if you just want to play games; it's about as close to SteamOS as you get w/o an official release

Any of those should be pretty friendly to users new to Linux, and they go roughly in order from fitness as a regular desktop (top down) to fitness for gaming (bottom up), but any of them can handle gaming and desktop stuff pretty equivalently.

Yes, it's only a fraction, but most of the rest is going to SaaS through web browsers or mobile apps, because companies get to control and force subscriptions that way, but has a side effect of targeting a browser as a platform rather than an OS. Gaming in browser is more in the pain point of browsers, so it's a use case that demands OS.