There is no "coming home" if you work 140hrs per week (or 130, as MM claimed to have done in Google for years). I doubt it is sustainable by anybody (4hrs of sleep per night are simply not enough for anybody- assuming you can go from "work" to "sleep" and vice-versa in 0 time, excluding showering, dressing, teeth-brushing, eating and going to the loo-, you become unable to perform any intellectual job on that schedule). I suspect these figures come only from an extremely loose definition of "work" and are further inflated like the proverbial fish of fishermen's tales.

Probably the only hard limit to these claims is the fact that there are 168 hours in a week, otherwise it would be a contest between this CEO claiming he worked 190 and the other replying she worked 300.