Same reason your main drive in Windows is "C:" - history.

The command-shift shortcuts (function keys as they were called) were added in the 80's as such:

Command-Shift-1: Eject internal floppy

Command-Shift-2: Eject external floppy

Command-Shift-3: Take screenshot

In the System 7 era in the mid-90's, Command-Shift-4 to select an area to take a screenshot of was added.

Back then you could also install FKEY code resources into the system file to add custom ones, there was a small ecosystem of freeware/shareware function keys with useful shortcuts people would install.

Have a cup of coffee, then come back and read your comment again.

You really didn't have to create a new account to say all that

> not always Command+Something. Go ahead, try to reopen the last closed tab on anything you're using, with the keyboard. Whooops, you pressed three keys.

Not always JUST Command duh. It still includes Command champ; the rest are modifiers.

I mean just ask any AI to list out all the common shortcuts for macOS and for Windows, then see which is more consistent.

> partial screen shot or record the screen ... Why did you press 4 and 5? What do 4 and 5 even mean?

4 alludes to the 4 corners of a rectangle, and 5 includes the time dimension, of course :)