Life isn't just a series of context switches between being productive at work and wasting time at home. The goal is to be intentional with how you spend your time.
For example, coordinating a social dinner with friends isn't work, but it also isn't a waste of time. Going to the gym isn't typical productivity, but it isn't a waste of time either. Even playing video games to catch of with old friends isn't entirely a waste of time.
However, the modern world is full of traps that will lull people into spending their time in ways that feel enjoyable in the moment, but feel wasteful in retrospect. It's easy to pull out your phone and scroll Twitter for 30 minutes, but it takes more effort to pull out your phone and call and old friend or a grandparent for a check-in. It's easy to drop on the couch and select from an endless series of TV shows on Netflix and Hulu, but it takes a little more effort to go for a walk or go to the gym. Afterward, which of those two activities feels like a better use of your free time?
> The psychological rigidity and social sacrifices required of always being productive (with little to no unstructured leisure time)
Is this really a common goal, though? I've been around some extremely productive and successful people in my career, but none of them held any illusions about minimizing leisure time. I've also been in some high pressure and highly competitive environments, but the number of people who adopted an "all work and no play" approach to life was vanishingly small. In fact, the people who are most motivated at work are often most motivated to arrange the after-work get together, or the weekend trip for the group of friends, or to invite people over for home-cooked meals so we can catch up.