Not all hours are created equally.
I do my best work with hyperfocus.
I don't just mean more work, but far higher quality work that's at the edge of my intellectual capabilities.
This is the work that's most rewarding and gives results that I'm proud of.
But I can't get significant time "in the zone" on a 40-hour week.
All the normal but necessary distractions take at least four hours a day, and I need at least an hour or two of "non-zone" work before I can hit my stride and achieve flow.
So I find 60-70 hours a week is essential to doing my best work.
But I can't sustain that level of effort continuously for years.
So I balance that out with a week a month of low-intensity "work" (slacking/procrastinating/socializing) plus at least twelve weeks per year of contiguous time for uninterrupted travel, long-distance trekking, rebuilding relationships damaged by hyperfocus, etc.