if you want high settings after 3 years you'd need 1070ti at least at a guess (and it is a guess. who knows what new gimmicks/bad optimisation will be around in 3 years)
if you're happy with dropping a few of the shiniest settings from high to medium (Anti-Aliaising etc) then the 1060 will last 2-3 years with 60fps
all this is based on you playing at 1080p by the way.