I worry that this already concedes too much. This allows for just as much stressful dominance of work over the rest of life, and shame over any deviation from this script, as maximizes productivity.
Even if my shorter-work-hours productivity doesn't match my longer-work-hours productivity, I'd still prefer shorter-work-hours, with no guilt over having those preferences. My goal in life is not to optimize everything I do for maximum benefit of my employer; I have my own priorities and trade-offs to worry about.