UIF and COIDA has always been there. It was either never enforced or the workers themselves were not aware of their rights.
The problem here was the assumption of the informality of the employment. Labor Relations Act provides clear criteria which defines an Employee and this specific section of legislation has been around for over 20 years, so it is nothing new.
One would then say the COIDA and UIF requirement has been in place for as long, just nobody enforced it, or perhaps knew about it.
Nothing unfair about this. With COIDA, if a domestic falls down someone's stairs and becomes paralyzed, would the owner of the house have a few 100k to pay them? Probably not, at least not all. In a more minor case, let's say they slip and break their ankle, will the owner pay them for everyday they are not at work and also compensate them for the homes they were supposed to have worked at.
This is why COIDA is needed, not only to protect you from a law suite but also the employee from loss of income. This is also not a major cost (R1450 a year for a 5 day domestic earning R400 a day) so I do not believe it is the reason, people just don't want to deal with the admin.