There was a brief period when all the big brains on the internet were convinced that UNIVERSITIES WERE DOOMED because online courses-in-a-box would inevitably replace them (well, not schools near Boston, but OTHER universities).
Then they just stopped talking about them, as they do when any dumb prediction blows up in their faces.
Of relatively non-important issues (unlike, you know, WAR), I think MOOCs and self-driving cars had the highest wrongness/(smug confidence) ratios from the usual set you get the smug confidence from.
The denomniator is always huge, so that numerator has to be off the charts!!!
(The fad died out before covid, but covid taught university administrators that distance learning was actually very labor intensive and they couldn't just replace the university with an app and expect students to be happy).