For Dylan, that means that Andy and Sherri and Craig and Seth and Kyle would just be sold to someone else. Andy and Sherri are in their late 50's/early 60's; Kyle's got a reputation for being mouthy. Any of them would have good odds of ending up in a situation where they'd essentially be worked to death.
Oh sure. Anyone in this society who inherited slaves and wealth is in a no-win position - they can't free their slaves, and there is no other moral way to get rid of them, and they have got to keep their income level at a point where they can support the slaves they inherited.
What would genuinely give this culture a chance of survival - at the moment, it looks completely doomed - is if there were enough wealthy slaveowners arguing that they want the legal right to free their slaves - putting the position that when their slaves have put in a lifetime of service, they want to be able to free them and give them a pension. Once you establish that there is a legal way out of slavery short of dying, that right can get expanded on. Not that I want this culture to have a chance of survival - it is interesting as is.
As for influence, compare Kate to Dylan. Kate's got her blog, and she goes to meetings and does activist work, and that's important. But the only slave she's ever really talked to is Paul, and she's had no measurable impact on his life.
Well, look at it this way: Kate's life has an impact on every free person she meets to whom it has never occured before that there was any alternative from desperately striving to make enough money to get out of the at-risk-of-slavery income group. If Kate is part of the network of people supporting each other from sale for slavery, she gives these people an alternative, more workable hope. (Yeah, I know these networks are something I just made up. But it would surprise me if the low-income abolitionists hadn't thought up some such scheme.) Maybe some of the people Kate's met and talked to joined a support network and were saved from being sold as slaves. Maybe they talked to others. Maybe Kate has changed more people's lives than Jeff has. (Dylan, as a lawyer, we know has the opportunity to change a lot of lives - the slaves of Kyle's former owner, for example.)
I'm not saying that he's a perfect altruist by any stretch of the imagination, or that he doesn't have selfish reasons for owning slaves. It's that the nature of the world means that refusing to own slaves ends up being a symbolic gesture which, while noble, doesn't do anything toward changing the facts on the ground for any individual slave.
Well, it's possible. After all, I just thought of these support networks. But I bet there's more and smarter people out there who refuse to own slaves and who work towards abolition than the twitty guy Joe meets at the supermarket door.