My theory many years ago still holds true. When building a gaming PC, spend more money on the CPU than the GPU. I bought a i7 2600k instead of a i5 2500k back in the days. The difference between the 2 was minimal. Cut to 2017 the i7 2600k still holding strong but the i5 2500k is not cutting it now.

The demand for the top tier CPU's for each socket is very high cause many people decided to "Save money" and go for a i5, i3, pentium years ago. I predict that the i7 7700K will hold it's value for a long time and demand will increase 10 fold when games will require more than 4 threads.