My theory is that due to their young age, two teachers can only manage ~10 kids on average, assuming each one is paying 1000/month on average, that's 10000 per

My theory is that due to their young age, two teachers can only manage ~10 kids on average, assuming each one is paying 1000/month on average, that's 10000 per month, after admin/rent/tax/insurance there are not much left to split between two staffs. Daycares are very local and can not be too large in size, all in all there is not much economy of scale.