As seen on reddit: an old Bill Joy quote often banded about as part of the (largely synthetic) vi-vs.-emacs holy war starts as follows:

vi was written for a world that doesn't exist anymore

The context of that quote is:

I was trying to make it usable over a 300 baud modem. That's also the reason you have all these funny commands. It just barely worked to use a screen editor over a modem. It was just barely fast enough.

9600 baud is faster than you can read. 1200 baud is way slower. So the editor was optimized so that you could edit and feel productive when it was painting slower than you could think.

(source: the register).

Furthermore:

unless you decide to get a satellite phone and use it to connect to the Net at 2400 baud, in which case you'll realize that the Net is not usable at 2400 baud.

You don't need anything as esoteric as a satellite phone: a cellular mobile phone will suffice. I've no idea what the effective/equivalent baud rate of GPRS is (or EDGE), but I have a new-found appreciation for vi's design goals having tried to run an SSH session over such a connection.