I think that the belief that leisure is a uniquely human trait, or that our relationship with leisure or happiness is drastically different to the past is wrong. Sure, there are things that have changed, technologies that change how we relate to things in the world, but happiness is a merely an emotion, not something relative to some civilization or lifestyle.

People in the past experienced anxiety, happiness, etc just as we do. It's hard-wired into our biology. Thinking that we live in this unique moment of history is absurd.