People still play games on 4,5,6,7,8 year old systems. All depends on what you expect out of the system. If you will be looking to play at 8k resolutions at 340hz in 4 years, then no. If you are talking about new games at 1080 at medium settings, probably for a while. I had a first gen i7 system with an nVidia 460 card that one of my kids were using still running new games up till a year ago, that's about a 7 yr old setup before I sold it.
Why does it really matter though? When it starts not to do what you want it to do, look at upgrading then. Wondering/worrying about the future for something like a gaming system is a waste of brain power.