(Especially not to the point of having a composited desktop; long tail game compatibility is less of a critical thing since, well, there are next to no games for ARM Linux...)
This was 3 years after the hardware release, presented on substantially more locked-down (but x86 and PC-like GPU to be fair) hardware with a demonstration of Portal 2 running in real time. Presented by the person you are replying to. I'm also assuming there was no funding involved given the requirement to build an exploit just to boot anything on the PS4.
As an unabashed cynic myself: Your cynicism as someone uninvolved with the project is outweighed by the informed opinion of someone who has demonstrated ability in the field of porting linux to other platforms.
This would be adding support for a completely different GPU, which is a whole different ballgame and order of magnitude of complexity.
That said, as many hours as went into the PS4 Linux project, it was a hobby thing and I'm pretty sure if you add up the hours spent on the GPU side it wouldn't hit one month's worth of full-time work. I'm also offering a whole different order of magnitude of time investment here.
