Jobs was a salesman. He said a lot of stuff - and not all of it stood up to scrutiny.
He said no one would use phablets and called them the 'Hummers' of phones - this was back when a 5-inch phones were considered huge. He also denigrated 7-inch tablets by saying users would need to file-down their fingers to use them (and yet iPhone users could comfortably use 3.5-inch screens). Apple proceeded to profitably venture into both product categories with the iPhone 6+ and the iPad mini.
We are now in a post-'Post-PC' world: iPad sales have plateaued/slumped over the last couple of years. If there is money to be made selling computers, Apple will sell them regardless of what they said in the past.
[0] https://www.youtube.com/watch?v=YfJ3QxJYsw8