Well, right. The IETF thought that what people really wanted was a circa-1992 Internet, and they'd put up with a little transition pain to get back there. They were wrong, and that's why nobody switched.
My point was that the IETF wasn't so naive as to think that the world would move to a new protocol simply because it was "the right thing to do". Their mistake was in misjudging the perceived value that IPv6 had over IPv4.