Why is it called Windows 10, not Windows 9

I think your logic is reversed. Because MSoft is “too big of a company” , they don’t use focus grous. They already know they’re the biggest bully on the playground, and they don’t give a damn about the little guy, what anybody else prefers.
Or, perhaps more likely, they do have their own , permanent, “focus group”, consisting of the same handful of tech geeks who’ve been coding all day and night for 15 years and live their entire lives inside the Microsoft campus.
The whole company lives in an ivory tower, so far removed from the real world that they simply don’t know what an average computer user does with his computer.

Microsoft does lots of usability testing with regular people. Even so, they sometimes end up with results that seem to defy logic. Why is Shut Down on the Start menu? It’s there because when they asked users to try to figure out how to shut down Windows 95 (the first version of Windows with a Start menu) most of them opened the Start menu. So Microsoft concluded that Shut Down should be on the Start menu. Many other seemingly strange decisions were made due to usability testing. Usability testing, like any other tool, can be done right and it can be done wrong but there’s no denying that Microsoft does it - they do a ton of it.

Yes, I agree that is what he was referring to. And he was asserting it has a 2K byte (or 2K character?) length limit. Which it does.

And which I asserted was due to back-compat reasons. 3rd party apps read those values and do things with them; they’re not solely for the use of the built-in cmd.exe.

And apparently there are enough of those 3rd party apps that crash that MS decided to leave the limit alone.

I agree completely with you that as disks get bigger and folder hierarchies get deeper, 2K can be pretty limiting for the PATH variable.

I mentioned MAXPATH, which is a completely different concept, simply as another example of a string whose length is fixed by back-compat problems which is now short enough to be a significant limitation even though it seemed pretty generous when first introduced 20+ years ago.

Perhaps Windows 10 will be the one where Microsoft finally moves past their traditional breadboard/S100 programming style and produces a well-crafted forward-looking OS design. All they have to do is burn some of those legacy bridges and force the Windows ecosystem more towards practical lines.

Shut down being in the Start Menu is often cited as an example of something counterintuitive or contrarious, but really, it’s nothing of the sort. Sure, it has the word ‘Start’ on it, which is kind of the semantic opposite of ‘Shut Down’, but its not the functional opposite. You dont use the Start Menu to Start the computer.

/rant

They only called it the “start” menu so that they could advertise it with a really horrible song.