Six years is definitely stretching things. First, that's assuming one of your major components like the motherboard doesn't die. Second, as CTurbo said the 1080 will likely really be showing its age four years from now.
To give you an example of that, four and a half years ago I bought a $520 GTX 680 high end card. It's now effectively useless in today's games even at 1080p. Here's an example of Witcher 3 with a 770 which ran a few FPS higher as being a 680 refresh:
http://www.guru3d.com/index.php?ct=articles&action=file&id=24968
As far as chipset itself (CPU, motherboard), think about six years ago and when Sandy Bridge first came to being which will be six years in January. It is showing its age and has been for at least a year now...