That's a really good theory, and it makes a lot of sense.
I think there's something else going on too though. The Egan family is so obsessed with themselves and their legacy. I suspect they see this project as some sort of path to immorality. Some sort of consciousness transfer into the body of a new host. Maybe they get to live with the other consciousness. Or maybe they overview that consciousness completely.
And I think that's an underlying motive for this project. Kind of a twofold benefit: they get to make a financial killing by selling throwaway innies to do unpleasant things (your theory); and they get to perpetuate themselves after the death of their physical body.