Far Cry 5 is already hard to have a steady 60fps at 4K, so future titles like Fallout 76 will struggle too I imagine. Nobody 'needs' anything. Obviously these cards are for the enthusiasts crowd. Do we need cars that go over 100mph?
For me, anything over 60 fps is icing on the cake. The thing about next gen video cards is that they can run newer games for a longer time.