This was never literally practiced.
But excessive hours were the norm. And I loved it. It helped me launch into a successful career.
But it hurt my relationship with my partner (now wife), and it burned me out.
I miss those days, but I don’t miss what they did to my health.
I've done the 36-hour straight work grinds, and working from 10 pm to 6 am for multiple days a week. However, I'm tired of doing that, and I've experienced enough burnout already. I'm also not okay with doing highly skilled work for more than 40 hours a week for pay that is almost demeaning—in the range of 35-45k a year. I'm more okay with it at a startup because at least the pay isn't THAT bad at more established ones with multiple rounds of funding. Just like the author, I have people in my life I'd rather devote time to because they bring be happiness. I'd like to have the savings to do practical and important things, such as do on vacation (which I find immensely good for my mental health), buy things for my other hobbies, and buy a house and have enough money to raise kids.
At least in Switzerland, I've heard your coworkers look down on your for NOT taking breaks and leaving at 5. The stipends are a bit nicer. Maybe it's worth it there. Maybe it's worth it anyway because the lack of CS jobs now will translate to requiring a PhD in the future. Maybe I should go through the extended hazing ritual known as a PhD because a startup's work won't be as technically rewarding as a PhD (the only person I know who wanted to do a PhD is now at a startup).
I still don't think the way we want people to work like this is okay. Sometimes I am a 996, but I sure don't want to be one when I need an extrinsic voice screaming into my ear to keep going because I'm not allowed to take a break.