">" prompts aren't that uncommon outside of DOS, though

    $ telnet
    telnet> 

    $ irb
    irb(main):001:0>

    $ echo look at me i'm an unterminated string
    >

I guess python's ">>>" prompt is more robust against accidentally being interpreted as a redirection, at least.

Makes sense, but weirdly I did not follow that route. I started on Unix, then learned about DOS, did not use it much, but I did switch my Unix prompt to use '> ', because I liked it better. The default '$' has too much visual clutter for me. BUT, when I post snippets of shell commands on the web, I use '$ ' because most people are familiar with it.

No. That's what DOS prompts looked like for people who knew how to alter them from the default, or who used quite late versions of DOS. The default prompt in COMMAND was $n$g not $p$g .

   A>

I wrote “normal”, not ”default”. Almost every autoexec.bat file I saw in the wild contained “prompt $p$g”.

You didn't see very many, then. There were lots of people who didn't have that.