I don't think the 1060 will be a max settings GPU at 60fps in 3 years. In fact, the 1070 may not be able to either. Look at the previous generations GPUs, such as the 960. The 970 was released 3 years ago and can it run 1080p gaming at 60fps with max settings? No it cant and it is not even close. The 970 can run today's games at 60fps either.
With that being said, the both are really good GPUs. So I would get whichever one you can afford.