[shams93]

We're hitting a ceiling based upon how many hours a single human can work without dropping dead from sleep deprivation, when you talk about 90 hours a week that means living at the office, over 90 hours a week and you're looking at only 90 minutes of rest per night 7 days a week.

[beckingz]

7 days * 24 hours = 168 hours per week. 90/168 is only 53% of the total hours in a week, and leaves 78 hours for non-work, or 11 hours per day.

Which is an insane amount of time and probably does not actually increase productivity. The math does not check out as you claimed though.

[MichaelCollins]

We blew past the natural limit many many years ago, except the limit was artificially raised by the normalization of performance enhancing drugs (namely tea, coffee, etc.)