Great questions.
Slavery isn't common. Crime lords are the main users of slaves. Slaves have no social status, are viewed as property, and are looked down upon in every facet of society other than perhaps the sex industry. I guess a rich person could own slaves and have them do those tasks but they would be looked down upon. It would hurt their social status. Their friends and neighbors would make fun of them. Slaves generally don't live with free people or associate with them (an exception being the sex industry). It has to do with the culture of the game world which is different from ours in many aspects.
Another reason is money. Why have a slave take a maid's job when you're paying the maid 10 caps per day and if she was a sex worker she'd be making 5 to 20 times that amount. One slave doing sex work would give you enough money to hire 5 to 20 maids. It doesn't make sense financially.
Slaves are mentally broken and require extensive training to become a proper slave. Slavery isn't like it was in ancient Rome. Slaves don't make good mothers or do jobs that are intellectually challenging. They are three holes to fuck and exploit for crime lords to make money off of.
Mabuta is a powerful crime lord that controls the sex industry in the area you live in. He also controls camwhoring. Yes, slaves can become camwhores. See the below post on why Mabuta also controls camwhoring:
https://f95zone.to/threads/evil-2-v0-76-community-project.41582/post-17234562
Additional Game World Info