A huge crux of his argument presupposes that Sony can only do top of the line graphics and are incapable of not doing so. They don't even have to put their 'top exclusive' on the console; anecdotally, I don't even like their 'top' exclusives, so I skipped over their Uncharted and Killzones and went gungho on their Japan titles, like Gravity Rush and Soul Sacrifice, 2 title styles which, at this point, likely won't see the light of day again. The only Sony exclusives worth keeping an eye out for (again, anecdotally/personally) are Sony Japan's offerings and GoW, which were fine enough on the Vita.
There's also a design philosphy concern. He mentions Turn-based RPGs being fine on the phone, but pretty much every phone-based RPG I've played has had a noticeable decline in my ability to care about them due to the nature of the device and the main component Dedicated devices have over phones: the controls. That doesn't even bring into account action games, which I pretty much skip on principle due to the same concern, but amplified because 'Action' game. There's also the fact that just because it's a turnbased game doesn't mean I'm willing to or desire to put up with latency. Persona 5's hud is glorified for its snappiness for a reason.
There's also the matter of ecosystem. I play mainly lower-tier titles on Switch due to portability but the Switch doesn't have achievement/Trophy tracking. If Sony had an equivalent console that still offered a tether to that ecosystem that I've built up, I'd jump ship back in a heartbeat. As it stands now, the Ps4 is probably my least favorite system I own because I have the switch for Portability and the PC for Power.
The Vita's biggest enemy was Sony, not anyone else. 3ds stayed popular despite being a pretty awful piece of hardware because it had things people wanted, relative ease of use and, most importantly, Support from Nintendo. As someone who engaged with the Vita Day 1, I feel pretty confident in saying that Vita fans were such in spite of Sony doing the exact opposite of all that at pretty much every turn. The Content Manager sucks, the Proprietary Memcard sucks and Sony's lack of dedication to the console sucks.
