@nannyofcelebrities no problem with your questions at all!
I'll give figures in Thai baht so you'll have to use XE to compare, but a full time nanny here could be paid as little as 12 or 14000 a month, up to mid 20s. 30 is unusually high. Western foreigners generally pay at the mid-high end; Thai, Chinese, Indian employers are more likely to pay at the lower end and expect more in terms of hours. That is a massive generalisation, of course, but there is some truth to it.
For live-in, all costs should be covered (including all meals, either with the family - though most don't eat with their nannies - or money to sort their own food). My nanny does either, she has access to as much money as she needs for food, toiletries, taxis, getting the kids an ice cream etc. We don't even record it now, she just lets me know if the pot is running low! But if she wants to eat what we're having, or if we go out for a meal or order a taekaway, she is always welcome to join. You do see families out for meals in nice places with their nannies and they don't even get the nanny a drink, let alone a meal. The first time we went out for food during a day out with our nanny, she seemed confused when we gave her a menu and I had to reassure her she could order whatever she wanted. She ordered the cheapest thing, haha! Now she knows she can have what she wants.
So yeah, the pay is dreadful from western standards but nannies on 18 or 20k a month are out-earning much of the Thai population. The minimum wage here is well under 10k a month for 6 day weeks (6 or 7 day weeks are normal here for all low-level workers e.g. factories, restaurants, gardeners). A good employer should give a nanny one month salary as a bonus every year, too (I give more than that but split into 3 payments over the year so I can afford it).
To put it into context, my nanny (young and single) has nice clothes, days out, even little holidays with her friends, a laptop and decent camera... And she has bought land and built a house in her village. She has achieved this in about 3-4 years, as the first year she was with me she was paying most of her salary back to her mum and putting herself through language classes, too. Since those expenses stopped, she has worked on paying for the house. So she has set herself up very well financially while still in her 20s. But the numbers just don't work in a westerner's head!!
For me, the 12/6 was there at first because my husband and I both worked and there is little in the way of daycare here (due to the nanny culture) and no wrap around care at school. So she had my then-youngest from 6.30 when we left for work, and then she was there to help with bath/bed when we got home. Saturdays she didn't always work, but it allowed us huge flexibility to have her available. It took her some getting used to that we would give her time off if she didn't need/want to join us on a day out or whatever. My nanny also keeps the house (washing, ironing, cleaning) but we are very clear that this is only when she has the time. During school holidays, she keeps the house vaguely presentable but I don't care if she hasn't done a 'proper' clean because I know I wouldn't have done so if I'd had my hands full with children all day!! Now they're all in school, so she does a bit of cleaning etc during the morning and then is a nanny from school pick-up til bath time. I'm definitely unusual in how flexible a set-up I have with my nanny, but it works for us. We are very much a team; since I've been on my own I would say she's as much a co-parent as a nanny!
Regarding employing just one person to work such long hours, all I can say is it's totally normal here. There are certainly lots of families (especially rich Thais) who have multiple nannies, housekeepers, a driver etc, but many people have one lady who does the house and helps with the children. Even families with a SAHP. I see more nannies at school pick-up than parents, and this is not because all parents are working. For us, when school runs became tricky with another baby in the mix, I hired one of my nanny's friends on shorter hours so she mostly did the cleaning while my nanny had the baby, then she minded the baby while my nanny did the school run. They just shared out the roles how it worked for them so they both got proper breaks, and it was a great opportunity for her friend because she was able to get experience and a reference from me when we didn't require her anymore, and this led to another job (a good one, with a nice couple!) as a cleaner.
One thing that won't surprise you but might surprise people unfamiliar with this kind of very involved nanny, is that she has also had my children when I work away. So, full responsibility, for 5 whole days, even sleeping with them (2 of them sleep with me and would be horrified at the thought of sleeping alone!!) Of course I gave her a big bonus for this, and I made sure my neighbours were all around in case she needed anything. But I never imagined this before I lived here. I suppose single parents without family support just can't work away without this sort of help and I know I am very lucky to have my nanny.
In terms of holidays, Thai law specifies a certain number of public holidays, maybe 15? So there are many people here who literally work 6 days a week, with the odd random day off, and then 2 or 3 days off in a row for New Year and Thai New Year (in April). And those are the legal ones... There are many who don't even get that. My nanny gets all public holidays as long as I also have them off, plus any time I take my kids away. This varies, it could be 2-3 weeks in addition to the public holidays, or 5-6. Some nannies get lots of holidays when their families are away, so they actively seek employment with foreigners for this perk. Sometimes my nanny wants to come with us - she came to the UK with us last year which cost a fortune but it was a once in a lifetime thing for her and worth every penny. She wasn't really 'working' on this trip as she stayed with another family member (we couldn't all fit in one house) and she could choose what she joined us for and what she wasn't bothered about.
Getting the visa for her to come to the UK was an interesting process... I was advised against applying for a tourist visa as it would likely be rejected, although she was in my opinion going as a tourist, a guest of my family rather than an employee. So we applied for a domestic worker visa. This seemed on the one hand designed to prevent human trafficking and modern slavery, with very detailed questions about her accommodation (would it have a locking door? A window? Ventilation?) and freedom (would she be in possession of her own passport?); on the other hand it seemed like a process to prevent her disappearing and illegally staying in the country (which she would not wish to do in a million years!! She loved visiting but would definitely not want to stay!) And anyway, nobody checked on what we wrote on the forms, so it was all just red tape and wouldn't have kept her safe if we had been trying to traffic her.
I can absolutely believe the stories you've heard about abuse of nannies from developing countries, and for sure it takes place here, too.