The mathematics of working ?

In recent times, there is a lot of discussion around how many hours one should put to work ? Perhaps, the more popular the statements were, they had one thing in common - they stemmed from people who had the luxury to have their daily alighting points at arms distance from their armchairs or workstations; drivers driving their decent or in some cases luxurious cars so that one could still work while being on the move; in some cases an in-house gym; and in all cases a publicly listed company. Of course, to reach this level a lot of hard work in initial days of career would have gone which merits respect.

Having said that, an average Indian, in a Tier 1 city has a residence (mostly rented or in beginning of career a PG) and in all likelihood far away from commercial / office locations or business parks such that 1-2 hours are spend on commute (one way) which BTW is an accepted norm and we are used to it. This leaves us with only 20/24 hours. The same people are also the brand ambassadors of either yoga or gym or aerobics so 1/24 hours can be attributed to that as well. In their other lectures, they are seen advocating spending time with the family so let's say 1/24 hours is spent in talking with parents, children, spouse, sibling and friends (not all on the same day but in parts); They have also advocated spirituality at some point in life in few lectures so say 0.5 hours attributed to it and they also love reading for which we need say another good 1.5 hours; BTW they also like reading newspapers, magazines and staying up to date by watching useful content so let's minus another 1 hour from the schedule; Of course, unless fasting an hour might go in consuming breakfast-lunch-dinner (BLD) and if you have to cook then 1 more hour goes into it.

Assuming one was sleepless, yet the best case scenario turns out to be 24-4 (Commute) - 1 (Fitness) - 1 (Family / Friends) - 0.5 (spirituality) - 1.5 (Books) - 1(Newspapers/Magazine/ Knowledge videos) - 1 (B/L/D) - 1 (Cooking) = 13 hours. If few of these are skipped, though inevitable, then there is a Work Life Balance concern in the mind of same group.

Question is, if this is practically not feasible, because about 9 hours could be spent in addressing daily needs, without sleep, then what was point around suggesting that X number of hours minimum one should work ?

A world without sleep would lead to failed surgeries, air crashes, road accidents isn't it ?

Would one like to be operated by a Doctor who hasn't slept for 2 days ?

OR, driven by an Uber whose driver hasn't slept for a day ?

OR, carried by an airline whose pilot hasn't slept for few days ?

OR, Taught by a Professor who is constantly yawning ?

OR, be a parent whose son or daughter hasn't spoken with them for few days in the age of IT and Telecom ?

OR....

It's easy that one can suggest the minimum number of hours to others, but the underlying cost can be at times too much.

No. of Hours in any country = 24

(Minus) Commute = 4

(Minus) Fitness = 1

(Minus) Family / Friends = 1

(Minus) Spirituality = 0.5

(Minus) Books = 1.5

(Minus) Newspapers / Magazine / Knowledge videos = 1

(Minus) B/L/D - 1

(Minus) Cooking - 1

(Minus) Sleep - 0

13 hours