He said the console was a mistake. It sold over 80 million units. Give me a break.
Give you a break? Give me a break. It's a gross oversimplification to conflate hardware sales with how well a system was designed.
The Playstation 1 and 2 were both two of the most commercially successful systems of all time. And neither one of them was designed very well. The quality of a system has almost nothing to do with that system's commercial success. This principle has held true for almost every home video console. Better designed and/or better performing systems do not necessarily win out in the marketplace.
And even if we take your flawed premise at face value, you are still ignoring the relative commercial success of the PSP's. It's closest direct competition at the time of its release was the Nintendo DS. How well did it fare compared to that system's sales? The PSP was notorious for being sold at a loss when it was introduced, despite it's $250 USD price tag. And it was also notorious for having one of the lowest software attach rates, thanks to rampant piracy on the system. Both of those factors are directly linked to Sony's decision to incorporate optical media into the hand-held.
"Mistake" is being generous. The PSP was a débâcle in the market. 80 million units or not. And the lack of success for Sony's hand-held line is only emphasized by the current struggles of the Vita. The Vita is arguably superior to its predecessor in every way, and yet it's still languishing.