For those who have done it -- does wrangling the kid really take ALL your time or is there downtime throughout the day? What's to say you can't let the kid play in a safe space/playpen for a while? Naps, etc? Do you get (god forbid) sick of being with your own kid?
Looking after children is not hard in itself, it's just hard because it's relentless. There's downtime. Babies and toddlers sleep. Kids older start going outside to play ball, or sit down and read books. And every parent has used tv as a babysitter. So there's downtime, but it tends to be unpredictable - you don't have scheduled coffee breaks in this job.
Yes, you get sick of your kid at times. Same as any job. Children offer you the greatest frustrations of your life - but also the greatest joys.
Men are, in general, better-suited to be the stay at home parent for a number of reasons. Obviously I am speaking in generalities, as I said earlier this is inevitable if we do not want each forum post to be a doctoral thesis. I speak of trends and tendencies.
Women are prone to post-natal depression. This is partly hormonal but also because of the frequent social isolation and feelings of being imprisoned. Men of course can feel socially isolated, but we don't have the postnatal hormonal changes, so depression is less likely. And women even without children have higher rates of depression and anxiety than do men. Men are not immune to it, it's just much less likely.
Women are in general more social than men. They have more friends and make more efforts to stay connected to physically distant family. So the isolation of being at home rather than in a paid workplace hits them harder than it does men.
Women tend to earn less than men for equivalent jobs. This is mostly for two reasons. The first is that women tend to be less aggressive in salary negotiations and undervalue themselves, if there's a salary range of $60k-$80k, for example, they'll tend to ask for $65k while the guy asks for $80k. If she's been out of the workforce for some years, she'll be anxious about returning to work and will be even less bold in negotiations, just happy to have a paid job. But a woman who has a child and returns to the workforce quickly will ask for more money than one who doesn't, generally speaking, because she thinks of supporting the child, and she retains the career confidence she had some months ago.
The second reason women earn less is that any time someone takes time out of paid work, the career interruption cuts into their income and career progression for their next job. A gap of a few months or so before and after the birth is inevitable for simple physical reasons, but after that it could be straight back to paid work, or it could be years.
A man will likewise suffer financially from an interruption to his paid career, but his boldness in asking for more pay will make up for this to some degree. Thus, the family's long-term net income will be higher with the man interrupting his career for children than the woman.
Children need both parents around. However an "absent father" is not necessarily on the other side of the country - you can have the same address and be an absent father because you're working 70hr a week, so they never see you. Women tend to refuse overtime, and unpaid overtime even more. Men tend to do it, they're more obedient to inconsiderate bosses. Speak to Japanese women, for example, about their "salaryman" husbands - 50-60hr a week at work, and even at 7pm he doesn't come home but it's out to drinks with workmates and boss to suck up some more. This is one of the contributors to Japan having one of the lowest birthrates in the world. We see this in plenty of Western couples, too.
So a family where the mother works full-time will not have the children miss out on the mother much; but one where the father works full (and a half) time will miss out on seeing the father, quite often.
Statistically,
the most unhappy women and most happy men are those married with children. So this suggests that the so-called traditional arrangement doesn't work very well. Let's try it the other way.
Lastly, there's wider social change to think of. Men generally are assumed to be sexual predators and dangerous to children. This is why few men become childcare workers, school teachers and so on - we're one paranoid parent or nasty adolescent away from unemployment and a smear that will ruin our lives. If we have more men as stay-at-home parents this will slowly chip away at this vile sexism.
A man's place is in the kitchen.