PC gamers (I'm one) are willing to spend 600$ for a new GPU. I'm sure Playstation fans will pay 400$.
This is extremely flawed logic.
First of all, a big reason that people buy PS4s in the first place is their affordability over PCs. If people really were ready to drop $800 readily on gaming systems then PCs would be a lot more popular.
Second of all, not everyone buy $600 GPUs. They represent a small minority. Most people will buy GPUs in the range of $150-$200
Lastly, GPUs are completely different than what's being sold here. A GPU allows a computer as a whole to improve its performance considerably. For all games and many other applications included GPUs increase FPS, efficiency, quality of graphics, etc.
4K capability and increased FPS in some games is not at all comparable to the improvements a new GPU offers, especially at this price point