I don't believe for a second that Elon Musk works 100 hours a week plus hobbies and free time in any conventional sense of the word work. I don't believe that every random set of 40 hours in his 100 would be something that he would be happy to pay someone else to do. Successful people lie to themselves like this all the time.
Basic math. 168 hours in a week. -100 for work, -49 for sleeping 7 hours. That leaves 2.7h per day. Probably lose at least an hour of that for basic human body related activities and general inefficiency. So 1.7h for being a family man and hobbies per day? Plus time spent driving to and from said hobbies? Plus the hundred small things we don’t track? Yeah it’s BS