The current console generation (which is almost two years on the market now) is rendering to 2160p (and downsampling to 1080p if needed). So 2K is last-gen in 2018 and the new industry standard is 4K.
And it won't move much from there, because PC GPUs are now mostly used for mining "crypto currency", so PCs are stuck with what is left.
Depends on how you look at it.
Current console generation is 5 years and Sony has sold 74m copies of their PlayStation (MS sold around 35m Xbone). The Ps4 Pro is a fraction of that number and was released late 2016.
So the majority of people still play at 2k.
However, that will most likely change when the Ps5 is released.