Another thing to consider is:
Why do we have keys staggered from row to row? ‘E’ is up and to the left from ‘D’, when it might be more useful to have it be directly above.
Here’s a good review of one with a more rational layout:
http://www.dansdata.com/edkb.htm

There’s a good write-up of Dvorak here:
http://en.wikipedia.org/wiki/Dvorak_Simplified_Keyboard

Anecdotally, Dvorak is supposed to help prevent/help with RSI, which is why I’m interested in it. (I haven’t finished learning it.)

Apparently, world record speed typists favor Dvorak as well.

But imagine if a jam-less keyboard could have been built before the QWERTY system had become established, then ABCDEF… would surely have been more efficient than QWERTY… - at least for novice users. Assuming they knew their alphabet, there would have been less need to hunt-and-peck, and thus a higher speed could have been achieved. Hence, in comparison to this, QWERTY slowed down users, though, as you say, in a world of jamming keys, this allowed a more efficient machine, which was indeed faster than one which jammed often.

That reason has indeed been obsoleted, but it was never to slow down users.

As you say, it’s debatable whether QWERTY is a market failure; compared to DVORAK (allegedly designed for speed), the only unbiased test on record showed that there was no advantage to DVORAK.