Most probably do yes, but it's not a requirement to use any of Apple's devices. You don't need to do some command-line kung-fu to get around online account requirement like on Windows, you can just click "Skip" at the online account step, and that's it.

Perhaps you hear no complaints because unlike on Windows, MacOS does not spoon-feed you 10 screens of dark-pattern-riddled upsell ads with options of "Remind me later", "Yes" during set-up. It quite literally feels like being spat on, considering Windows is not a free operating system, and yet it still riddles you with ads and dark patterns as if some horrible shareware from the mid 2000s.

It's not really needed at all for macOS, but remains mandatory for even free apps on iPhone/iPad, so yes virtually all users have one. Same goes for free macOS App Store apps but that's not the only or even most common way to install stuff.

They might have all an Apple Account but thats not a requirement at all on macOS. Thats the difference between complaining customers and customers thatuse it because thez choose to use it.

No.