My parents were living this lifestyle. My dad routinely worked 100+ hour weeks, often sleeping on job sites and very often traveling for work. It kinda makes me chuckle a bit when I hear people say that 'nobody can do 80 hours!' when I spent my entire formative years watching my dad and everyone he knew doing exactly that but doing much harder labor.
It really feels to me like people who say this stuff are either very young, or have had extremely limited exposure to the world outside of their bubble.
