Do you mean in terms of contemporary released game titles and performance? Or do you mean physically working?
I have 20+ year old video cards that are still kicking around. A pretty good sample of all the technologies throughout the history of PC gaming. But obviously most don't work for running modern games (or are physically incompatible with newer hardware)
Fans are the most vulnerable part of a GPU. They may need replacement at some point. Next would be the power circuitry and capacitors. Though electrolytics are quite rare these days. The integrated circuits should last a long time, at least 10 years. (Though these newer process nodes haven't been around that long to really tell)