I don't think most who've found TTATT plan on staying in indefinitely. People just stay in until they can get out, or in an effort to get loved ones out with them. While we only have one life to live staying in the cult for a time is no different than other sacrifices we make. We work, do chores, etc because we need to pay the bills and these things, while unpleasant, enable us to achieve some goal that ultimately makes it worthwhile (hopefully).
Of course there are some that are beaten down and think that a life outside the cult is unachievable for them. Like an abused spouse their self-worth may be low and they may overestimate the difficulty of moving on. For these folks, I suspect a pep-talk about having one life to live probably won't make much difference. Hopefully any in this situation will eventually find their way here or somewhere similar to find the support they need and see all the examples of people who have made it out and live rewarding, genuine lives in spite of facing the same challenges that they do. That's probably going to be what gives them the push they need to make a change in their life.