I think there are a couple of really different types of situations these actors resolve. The fake groom for a wedding is just a workaround for a cultural issue

I think there are a couple of really different types of situations these actors resolve. The fake groom for a wedding is just a workaround for a cultural issue, maybe not uniquely Japanese. The society requires a groom, so here is one. I wonder how many politicians today have fake family lives due to similar reasons, for instance. But there are other situations, like fake boyfriends/girlfriends. What the company provides here is trust, sort or removing counter-party risk. The client needs to know that the friend will confirm to certain protocol, will be in a certain way. Many people would do that for free, but the actors are guaranteed to do that. If there was some mechanism to establish that kind of trust without the company, that would be nice. Without that trust, its just the usual dating, of course. And then, there is a commitment aspect. That man acted as a father for 8 years. The must have been growth in that relationship. The actor and the girl developed an inner world in which they exist, are part of each other's lives, and, the girl at least, relies on him to be there in the future. Many man could probably act as fathers for some time, but 8 years, they'd actually have to want to be fathers. edit: maybe its worth adding that this is not a suggestion that that business is a good thing overall. Just an attempt at the analysis of why it might be "booming" (if it indeed statistically is).