Is he right?

maybe in like 2006 lol.

On console GPUs he's absolutely correct, first off because developers can go as low level as to write actual microcode where DX11 and OpenGL have a lot of driver and CPU synchronization overhead, second because it's a fixed spec developers will get better at targeting over time. Things have really changed on the API side though since 2014, with DX12 and Vulkan delivering far more efficient and explicit programming of the GPU.

On mobile GPUs he's correct simply because of thermal throttling and battery life concerns. The mobile SoC you're targeting as a dev is always underclocked to some extent.

he still works at oculus on the software side though. he's still keeping up with everything

Cringe

I need to have a PC regardless, and it needs to be good enough for comfortable use. Why buy a 500€ PC and a 300€ console (+games) when I can just buy a 800€ PC? The library will be bigger and cheaper and the games will run better than on console

is this because consoles will run everything at upscaled 1080p and 30fps and pcs will run 4k60fps?

At the time somewhat yes, but his numbers were off IMO, it was more like 50% slower on average. This was before Vulkan/DX12.

I would say it's even now that Vulkan can be done on PC, consoles and mobile.

probably
os overhead and power source

the fuck does vulkan has to do with anything. if every platform using it then what changes here? what makes his statement false?