Not a startup, but on the birth of my second kid I committed to writing a technical book. About as hard as having a kid in my experience :) I averaged 60 hour weeks for about 1.5 years.
What made us not go insane was:
My wife was stay at home.
My wife supported what I was doing and bought in to the impact it could have on my career.
Grandparents nearby that regularly came to help out with the kids. My parents were very supportive (again they knew it would help my career)
I would wake up early on weekends and spend time with the kids so my wife could sleep in and have a break. This gave me 1-1 time with them. Usually I’d take them out of the house somewhere fun.
My main work wasn’t too intense. Indeed they even gave me some time to work on the book.
I’d say it’s doable if your full time job is laid back, your wife is fully onboard, and you have lots of extended family support. Even better if you can get your main job to invest or supportive!
Writing book is my another bucket list beside building a startup. Speaking about scope, writing book is still hard but seems more doable than startup.
I remember have skim your book, although I didn't read every pages. But as any good technical book and as you said, not everyone are having sufficient energy to average 60 hour weeks for 1.5 years. Put aside they are also a parent. :)
What made us not go insane was:
My wife was stay at home.
My wife supported what I was doing and bought in to the impact it could have on my career.
Grandparents nearby that regularly came to help out with the kids. My parents were very supportive (again they knew it would help my career)
I would wake up early on weekends and spend time with the kids so my wife could sleep in and have a break. This gave me 1-1 time with them. Usually I’d take them out of the house somewhere fun.
My main work wasn’t too intense. Indeed they even gave me some time to work on the book.
I’d say it’s doable if your full time job is laid back, your wife is fully onboard, and you have lots of extended family support. Even better if you can get your main job to invest or supportive!