Why are we using Indians as examples here? What about Italians, Britons, Japanese, Cambodians etc.? Just because Indians live in one house a whole family it makes it right? For most, it just works because the ladies are supposed to be somewhat docile. They take instructions from the husband, in-laws etc. Such an arrangement would not work in a situation whereby - as it should be - the lady/wifey has a mind of her own.
Unless you are jobless/broke or are taking care of a sick parent I don't see what you would be doing in your parents house. Ati your mum is asking "Mumebakishia Intelligensia uji?"
Does moving out make you more responsible? Of course yes! Does it work on everyone? No. Just like medicine, there are some people who develop resistance. That doesn't mean that the ones who would have responded to the medicine should not take it.
I am biased when it comes to the ladies though. My daughters can stay as long as the want to but as for the sons, they'll have to man up. @Magigi and @Impunity are some of the reasons I'd rather my daughters stayed at home.

.On a lighter note.
Never count on making a good sale. Have the purchase price be so attractive that even a mediocre sale gives good returns.