First, there are obviously diminishing and eventually negative returns to increasing work hours past a certain point. At the extreme end, 168h/week is clearly less productive than 40h/week despite being more than four times longer. At some point an additional hour provides zero marginal benefit, and past that point an additional hour lowers a worker's weekly productivity. That point may be 72h/week as "996" Chinese companies suggest, 40h/week as Henry Ford suggested, 32h/week as some 4-day workweek experiments suggest, or something else.

Second, even policies that provide some benefit to companies may backfire for society if they increase mental health problems, lower social cohesion, prevent family formation, and/or cause their best-and-brightest to leave. At some level the best way to "compete better with China" may be to focus on maintaining sensible policies focused on maximizing an individual's "life, liberty, and the pursuit of happiness" alongside overall national productivity and let short-sighted competitors burn themselves out. (Similar to the strategy adopted during the Cold War.)