It's also interesting that, prior to the iPhone, no one would have thought that phones would disrupt the PC market.
That might also be because iPhone happened to coincide exactly when 3G mobile broadband internet became available.
Pre and post 3G mobile broadband were different worlds.
There's some revisionism here: having the internet in your pocket anywhere you went was a clear upgrade. Projecting a screen on your palm with low resolution was a clear downgrade.
Disruption is incredibly difficult but this product was giving off Juicero vibes from the start.