I'm confused. Earlier in that Twitter thread he said that PS4 doesn't permit outputting games at more than 60 Hz. PSVR has a 120 Hz display. Did I imagine all the 120 Hz and 90 Hz games I played on PSVR?
Aside from that I really don't get the point he's making about BC/live service games.
He doesn't understand game development or game architecture.
To my knowledge PS5 will use an evolution of the GNM API for graphics, just as Series X will use an evolution of the DirectX API for graphics. Neither PS4 nor Xbox One launched with a GNM or DirectX version that PS5 and Series X will launch with, but neither will be entire rewrites, either.
Secondly, he seems to think the frame rate output of a game must be tied to graphics API rather than the engine that uses that graphics API.
Thirdly, he doesn't realise that PS4 has been capable of outputting 120Hz since PS VR. PS VR has three modes, with three outputs from the PS4 itself. 60Hz, 90Hz and 120Hz. Very few games used 120Hz (Polybius is one) due to the lack of power in the console to do any fancy graphics at that frame rate.
Fourthly, he doesn't really understand how games are often designed. Games with fixed frame rates often have game logic tightly coupled with the rendering loop. Sony want to vet games for this before essentially whitelisting them to run in the unlocked modes, with the compatibility modes as a fall back. A fall back Cerny was already bullish back in March that they might not even need.
This thorough approach to backwards compatibility is being interpreted as Sony games having a fundamentally different approach to how Xbox games are made and it's just not true.
In fact we've already seen a Series X video where some older titles specifically wouldn't launch.
Maybe the difference between the two companies is that Microsoft has an in-house team that patches and updates games, whereas Sony feeds back their findings to the developers?
The idea that Xbox games just work on Series X unlocked because of DirectX, and that PS4 games need to be "ported" to PS5 because the APIs are so different is nonsense until we get confirmation Sony has ditched GNM.