> There is an assumption that by now everyone knows what the menu in the bottom left corner does

Except that... it's no longer in the bottom left corner! Recently, I had to help a relative with a Windows system, and what passes for the "Start" button has now moved to somewhere more in the center (and, of course, this completely confused my relative, who was used to the old place). I also had to rant about Fitt's law (without mentioning its name) and how things were better the way they were before. And I also had to find out and show them where the shutdown button ended up this time, so they could power off the computer normally (as they were used to) instead of having to use the power strip switch.

And the issue I had to help with? Windows was too slow (to the point of nearly unusable). They don't use the computer often (and obviously always power it down after each use), so it's always running some heavy background update (on a mechanical hard drive) whenever it boots up. My advice was to power it up and let it sit for about an hour before using, then it would be back to normal speed.

You could've changed the setting that puts the button back on the lower left corner and saved your relative the trouble.

The new default is truly terrible, though, and this was the first setting I had to change when I was forced to use a windows laptop by the company I work in.