In the UK to be a nanny, childminder or work in a nursery you have specific regulation and qualification required. A babysitter requires nothing, it can and generally is some teenage kid.
The difference with all 3 is where the child go. Nursery has special dedicated facilities to take care of several children, number limited by the number of employee and size. A childminder will take care of 1 to 3 children in her own home. A nanny will come to your home and take care of 1 to 3 of your children.
All 3 are available in full-time ( i.e. working hour full time ) or part-time.
The movie type, stay at home Nannies are "Au Pair". Depending on the qualification ( from foreign student doing a bit of cleaning and getting the kid to and from school to fully qualified nanny ) the price varies enormously. Au Pair is not unusual, Au Pair Nannies is rich people stuff.
"Au Pair" means "on par" meaning living as part of the family. As such, au pairs get house and board and a small amount of pocket money, but no salary as such. They also don't have clear-cut work duties, they help around a house, as a member of the family would be expected to do, cooking, cleaning, washing etc. As a parent, you're generally not supposed to leave the au pair in sole charge of the children for more than brief periods of time (as you would a babysitter). That's the general theory, of course, individual arrangements range widely.
A nanny is a professional employee of the family, generally has training and certification, has clear duties and makes an actual salary. An "au pair nanny" is an oxymoron, that would be a "live in nanny" and, yes, definitely rich people stuff. Au pairs are definitely possibilities for the middle class.
Again UK-specific: They only _need_ qualifications to register with OFSTED, and as a parent, it's up to you whether you require your childcare to be registered. If you leave your kids with a friend, for example, your friend doesn't need any kind of qualifications. However, you can only get Government subsidies (like child tax credits and childcare vouchers) for a registered childcare provider.
Technically, the requirements are a little stricter: "You must register with Ofsted or a childminder agency if you want to be paid to look after children under 8 for more than 2 hours a day in England"[1]
In the example of leaving your children with a friend, the exemption is for a maximum of 3 hours (per day), if the friend is being paid. Any longer and the friend is obliged to register with Ofsted (with a penalty of an unlimited fine and/or jail for not being registered).
I doubt many people would think to check the legal requirements though.
Here in Spain I know a family that hired a young girl "au pair" (in their case a Polish girl who wanted to learn Spanish). The father told me they paid her about 400 euros/month + food and accommodation, so it's not something prohibitively expensive.
To use your numbers, a person would have to make less than $11,000 a year for that salary to be half their income. I doubt there are many people reading this discussion in that income bracket.
There are many things in life that aren't feasible if you are at the poverty line: Apple laptops, electric vehicles, extended vacations, etc. I would argue that the only difference here is that many people are deeply uncomfortable with the idea of paying someone to take care of their children in the home.
I am living abroad, and I will let countrymen/women correct me, but in Portugal you can hardly aspire to earn more than 1500 euros before taxes, in the best companies.
Most of them pay less than that.
So a university degree will land you around 1000 euros, a bit more if you are doing lots of overtime.
Renting a flat will always be above 300 euros, or 500 in the biggest cities.
So unless one if living with a significant other, and reserve one salary for such expenses, they aren't possible at all.
In Spain the salary level on average is around 25% more than on Portugal, but given the actual situation the real numbers on the bank account aren't that much different.
And I am writing about people with degrees, let alone those that only learned their profession hands on the job.
A nanny doesn't necessarily live with the family, but the 'primary care setting' (i.e. where they take care of the children most of the time) is the child's home. They can also be part-time.
The key difference is that a nanny is usually a formal salaried employee with regular contracted hours, whereas a babysitter is typically paid an hourly rate and is self-employed.
In the US in the 21st century vernacular (at least in NYC and Bay Area), nanny means child care provider with fairly regular hours, taking care of a smallish number of children (1-5ish).
The phrase "nanny share" is very commonly used. Sometimes the nanny is in their own home, sometimes in [one of] the parents' home.
Babysitter generally means someone who comes occasionally to watch a single family's children.
There are obviously fuzzy lines separating the two terms.
