Basically, people above answer "we'll tell you who is likely to be a market star after the fact." Talking about fly outs after the fact is a poor response to people's request for what a market star looks like.
Basically correct, yes. Market stars are defined by what happens to them on the market. That's how you operationalize "market star." The track record of predicting market stars in advance is pretty poor. We don't know what causes them to be market stars.
What are the characteristics of a market start that lead to their getting flyouts/offers?
Sometimes they have published a solo or first authored paper in ASR/AJS. If not they often have a solo/first authored Social Forces or a top subfield paper that's getting a lot of attention. If they're qual their book contract may be lined up already. Sometimes they use an innovative method (computational, experiments). The dissertation captures the zeitgeist of the discipline (if a random sociologist hears about the dissertation they get very curious what it finds). They tend not to do work on culture or religion.
But if it sounds like I have a good idea of who is going to be a "market star", that's not what's going on. Market stars have some set of those qualities but we don't know how many. The list of people who fit some of those characteristics each year is probably ~50 JMCs, and only a handful of people are market stars each year. So we have some idea who in that pool of ~50 JMCs is going to take off but we're wrong as much as we're right.