If that's really the case, I would expect that sororities would have a similar outcome. Every sorority member I know (it's not many though tbh) would say the same things about it making them a better person and providing strong social contacts to rely on.
But the article says sorority members had no income benefit. There must be another factor at play. The author did say the lower age of sororities could be a factor b/c networks are less established, but surely that would mean there is no corresponding benefit for men in new fraternities, which I doubt is the case. Either way, they should do a comparison that accounts for age of org and study the effect at women's colleges next (especially women's colleges that turn co-ed, since that would be equivalent to their subject here).
But the article says sorority members had no income benefit. There must be another factor at play. The author did say the lower age of sororities could be a factor b/c networks are less established, but surely that would mean there is no corresponding benefit for men in new fraternities, which I doubt is the case. Either way, they should do a comparison that accounts for age of org and study the effect at women's colleges next (especially women's colleges that turn co-ed, since that would be equivalent to their subject here).