I found it interesting to read both the original question and the responses with a Mustachian perspective in mind. I've read a debate about working parents vs SAHP elsewhere recently and it ended up being very "It's all very well for YOU to stay at home, but some of us HAVE TO work". Whereas most Mustachians could swing a SAHP no problem without getting into financial trouble, even if it detailed FIRE plans.
In my fantasy world, I would send my kids to boarding nursery 24/7/365 for the first year, have them back when they're one, send them to day nursery when they start being stroppy little turds, then have them back permanently around age three. Is this option available in the poll? ;)
We value having a SAHP, but holy fuck babies and toddlers are hard work. If I'd been earning enough to cover daycare, then knowing what I know now I would have worked part time until the kids' average age was four - then become a full-time homeschooling SAHP. (Note: our eldest is three...)
As it is, I'm a SAHP for the foreseeable, as the finances didn't make me working any kind of sensible option.
What's often missing in these discussions is the age of the kids, what age the adult in question would most enjoy being at home with them, and what period of the adult's life is likely to make most financial difference long term. School hours are short and school holidays are long. It's always worth having a SAHP if you want one. I suspect many SAHPs enjoy being with their children more when they are 3+.
I think one of the great potential gender equalisers of our age would be the widespread availability of higher level part time work. Part time lawyer, banker, management consultant, doctor... So it wouldn't always be the lower earning spouse who is more likely to be the woman who gives up their career completely while the man keeps his up completely. If they could both cut their hours back, husband could be a more involved dad and wife could maintain her career.
I think for a lot of Mustachians who earn a decent amount and have FU money, it would be possible for both spouses to go part time. More time with the kids but not overwhelmed by it 24/7, some money coming in but can coast for a bit on a reduced savings rate without a problem, maintain access to career to ramp up again later if desired.
The whole "raised by strangers" thing is something I have mixed feelings about. It does happen. You do get kids who spend almost all their waking hours being looked after by non-parent caregivers for years on end (e.g. nanny does morning routine and drops them at school, at school all day, nanny picks them up and supervises homework, dinner etc, parents pop in to read bedtime story between conference call and cocktail party). But working parents =/= uninvolved parents.
Going nuts because your 3yo won't leave you the fuck alone for hours on end doesn't mean you don't love them or you're not a good parent. It probably means you'll come into your own as a parent in a year or two's time. No one is medal-worthy at parenting every single age of kid. Some struggle with the teen years, some the baby years, others in between. Looking after a small baby is about as much fun for me as being a Hebrew slave building the pyramids. Doesn't mean I should never have had children - there's the next few decades of their life when I can enjoy them more when they're not up all night and screaming incoherently while being unabke to even point at what they want or move to get it.
Speaking ideologically rather than practically, we would prioritise having a SAHP during the primary school years in order to homeschool. I think that's when our kids would get most benefit out of having a parent available all the time.