That level of dedication came to me because I was not very disciplined when I was younger and hadn't developed any marketable skills. I grew up poor and I didn't want her to grow up poor. So I threw myself into something I had an aptitude for and I started working my ass off at getting better at it. Though, one could say that any effort is considerably more than I had put in before.
I really want what is best for my daughter. I have to give her a better life. So because it has become so important, that's why I work so hard. She interferes sometimes, but I'm not going to let that stop me from giving her a better life.
Not speaking from experience - I just have three kids, do what I can to take care of them despite being the primary breadwinner, and can't imagine the resentment that must stack up if you just drop all the sleepless nights and weekends of kid-juggling on your partner.
Never mind that you'll lose 7/8ths of the whole point of having kids with this approach, too.