Sure, but “being dumb” isn’t an exclusive club for people with low intelligence. There plenty of very smart people that are also dumb. Hell, most AIs could be classified as smart but dumb.

Wouldn’t the knock-on effects of a reduced attention span pretty much look like ‘dumber’?

I’ve been hearing that the “changed handle” thing isn’t valid, because when an account handle is changed you can still see the original on the user’s profile (and that wasn’t the case for the littlestjeff account). With all the misinformation flying around, I have no idea about the accuracy of this though.