Sure, but Valve is terrified of the Microsoft store for a subtly, but importantly, different reason than why Microsoft should be terrified of Steam OS.

Microsoft should be terrified that Steam OS will destroy their monopoly by making it so users no longer have to use their product.

Valve is terrified that Microsoft will destroy their monopoly by making it so users no longer can use their product.

There is nothing to be terrified of for MS, windows can implement mandatory rectal scans to log in and linux wouldn't break 20% market share.

Windows 98 was supported until almost a year after Windows XP's release, so nobody really had to use Millennium Edition. Windows 10's support is ending in October and no new version has been announced.

Microsoft always follows the pattern of good OS, bad OS, good OS, bad OS. We just have to wait for Windows 12 for a good one.

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%.

I had issues with drivers, like I would have to find them somewhere on the internet, trust a random stranger to download and install them. And even then some things required me to launch drivers manually every single time I wanted to use my hardware.

I had issues with games, constant crashes or some games flat out not working. Some even crashing the entire system occationally.

I had issues where my pc would randomly turn on. Going to sleep was funky and would break the system requiring restart. I had to find drivers for my audio systems to get them running.

I had to run around confusing settings and tweak them through different control panels made by random people that largely overlapped to fix basic issues.

Thankfully those issues were solved the moment I installed linux.

It's funny because while some of it has to do with work to make Linux desktops better, a non-trivial amount of it is how worse Microsoft has made it to deal with Windows.

They do. We're already there.

The only titles that don't work are the ones with kernel level anti-cheat, and that needs to die anyway.