Roughly 10.3% of U.S. workers belong to unions. But among workers under age 34, that number is only 7.3%. Under age 25, it’s just 4.4%. And the average person actually working for a labor union is 51 years old.

Labor unions are for older workers. They were already on their way out back when it was still common for U.S. workers, union or nonunion, to work for the same company for 30 years. That situation ended as people discovered that it was to their advantage to climb laterally within their industries. Today, many younger workers are eschewing the traditional employment relationship altogether, either dabbling in the gig economy on the side or diving in and making it their full-time jobs.