Today's New York Times article, "How Did Marriage Become a Mark of Privilege?", while focusing on marriage-rate differences by socioeconomic class, also incorporates discussion of the transition to adulthood. A couple of key paragraphs from the article are as follows:
Americans across the income spectrum still highly value marriage, sociologists have found. But while it used to be a marker of adulthood, now it is something more wait to do until the other pieces of adulthood are in place — especially financial stability. For people with less education and lower earnings, that might never happen.
College graduates are more likely to plot their lives methodically — vetting people they date until they’re sure they want to move in with them, and using birth control to delay childbirth until their careers are underway.
Indeed, as Jeff Arnett showed in a 2001 Journal of Adult Development article, only around 13% of midwestern U.S. respondents considered getting married as something that was necessary for adulthood (this figure did not differ much by respondent age). The other portions of the description, about planning and vetting, fit a standard description of emerging adulthood.
Like marriage, emerging adulthood is also linked to SES. As Katherine Newman (2012) notes in her book The Accordion Family, the better-off a family, the more capable it is of supporting emerging-adult pursuits such as unpaid internships. Some of the ideas given in the Times article for facilitating marriage among those less well-off, such as affordable housing for young adults, would also likely provide a stable base for emerging-adulthood-type exploration in the areas of work and romantic relationships.