We’re at that point in the timeline of new gen consoles where companies start putting out new systems with minor upgrades. Sony and Microsoft did it last time with the PS3 and Xbox 360 when they changed the hard drive spaces.
The PS4K is an upgraded PS4. The point of the PS4K is to give the gamer a richer gaming environment. Both models will run PS4 games so there isn’t a drastic change and the original PS4 isn’t out of date. The change will be the graphics. The games will run better on a different software. The PlayStation VR will run better on the PS4K due to the graphics. The original PS4 is good but, the VR can barely run on its hardware. For example EVE: Valkyrie, Robinson and GT Sport are PSVR titles that need that extra horsepower to get the full experience.
The PS4k is supposed to offer twice the GPU horsepower, a UHD Blu-ray player and maybe replace the CPU. Many developers are already making games that take advantage of the the PS4K specs. While existing games are expected to see any hardware upgrades there are a few titles that will support the new graphics such as God of War 4 and Capcom’s Deep Down. With all these upgrades the price is going to jump from $400 to $500, easily. The PS4K could be released within the first quarter of 2017. In case you were shopping for holiday gifts of 2017, just an FYI, PS4k isn’t a choice.