Some kids are just angels and sleep like champs, others fight every inch of the way and wake up constantly. As a result, different parents come up with wildly different “truths of parenting”.
Taking a few months of parental leave right at the beginning was such a big help. All of the above becomes so much easier when you simply do not have to worry about work. Baby is not sleeping from 2a.m. to 5a.m. every night? Or only sleeps when having body contact, such as sleeping on your chest? So what! Stay up, do some chores, play some computer games or watch a movie w/ baby on your chest (yes there's ways where you do not have to worry about baby falling off and you have both hands available, so you definitely can get lots of computer gaming done in that time ;)). Go to bed at 5a.m. knowing you don't have to get up to get to work and be expected to have a fresh mind. You just fall asleep, exhausted and wake up for lunch time and it's fine! It just totally takes the extra stress out of that time (of course you're still gonna be tired from having your sleep rhythms effed up and such and sometimes baby just doesn't want to sleep at all, no matter what you do etc.) and I believe that can make for better parenting overall. Back in the day some of that would've been taken care of by living w/ your parents or in-laws.
Baby wakes up at 6:30am like clockwork. Your move, parent.
Not to be a stick in the mud. You’re of course right that having additional responsibilities further increases the stress & difficulty.
As in I'm talking proper parental leave, meaning both parents can take 3-6 months off at the beginning, no questions asked, everyone is OK with it and it's totally normal. And you still get a reasonable amount of salary - in our case here in Canada from the parental leave part of E.I. meaning government guaranteed. Of course if I look at SV salaries, the maximums you can get under that program are laughable but here where we are it was totally workable at the time in our lives when we had kids.
Contrast that to what I hear about SV companies (I won't cite company names as that will draw the ire of the down voters here on HN, but I have inside knowledge i.e. new dads in such companies) where even if officially it's possible, nobody really does it. Sort of like "unlimited vacation", which sounds like it's better than the 30 days you get as a dev in most European countries but that in reality just ensures that nobody wants to be "the guy" that takes the most vacation and you still don't get more than you used to. If you were one of the "lucky ones" that had more than the minimum, you're now probably taking less time off than before.
This does not help if your parents are working, which they usually are.
Back in the day some of that