I think a better title might have been "Society can't optimize for rest". FIRE is a myth, only a small percentage of people will ever have the ability and means to do it. A few can optimize for their own rest, on the backs of the rest of us who cannot and will have to work until close to death.

I think the only way you optimize society for rest on the whole would be to determine how much and what kind of time off humans need at the maxima, and then figure out how to schedule humans for the work that cannot be automated based on that. Suppose a human needs to have a month of time off per 6 months of 20 hour a week work, then we should assume no human can work for more than 20 hours a week 10 months a year, minus some other safety margin. I don't think there is ever going to be a day where society is able to optimize for rest to the extent that it's really needed, the pendulum will never swing as far as it needs to.