What do you realistically need to double fps in an existing 30fps title?
Or to make better looking games, better textures, longer draw distances, higher poly models etc all need more memory, faster memory, faster cpu, faster hdd for streaming. HDR rendering needs more memory too.
At first the games need to be designed around this, so you're looking more towards multi platform game performance instead of exclusive type optimization. Yet maybe 1st party can afford to make Uncharted like games tailor made for both hardware specs, and most multiplats already have the option of higher fps on pc.
But it will cost a lot more money to optimize and test for 2 hardware specs at no extra gain for the publisher. They still sell the same amount, it's not selling to a different user base. So it will probably not get that much effort. Either the base ps4 will suffer or the new one will go underused.
This PS4K is nothing more than HDMI 2.0 HDCP 2.2 HDR compatible revision for video. Any slight upgrades in hardware performance will be for the UI and might at most stabilize fps in some titles. (And perhaps introduce frame pacing issues in others...)







