If anyone has shown a keen understanding of how to unionize workers in America, it’s David Rolf.

In the 1990s, he was a key player in the Service Employees International Union winning the right to represent some 74,000 home care aides in Los Angeles–the largest union organizing campaign since the 1940s. In his present post, as president of SEIU Local 775 in Seattle, he has spearheaded growth from 1,600 to 45,000 members. In 2014, The American Prospectcalled Rolf “the most successful union organizer of the past 15 years.”

All of which makes Rolf’s take on the collective-bargaining system–that it is a relic, and that those who truly care about workers should stop focusing their efforts on promoting it–particularly provocative.

“I think we made a valiant . . . bet that if we put enough talent and enough resources behind traditional union organizing that we could somehow bring back the old model,” Rolf told me on the latest episode of my podcast, The Bottom Line. “It wasn’t the wrong theory to try necessarily. . . . But ultimately, when you try something over and over again and cannot achieve the results you want, it’s time to try something new.”

Instead of being sufficiently innovative, Rolf adds, most labor leaders have been “reinvesting and doubling down on our American system of enterprise-based collective bargaining since the union movement started to shrink in the early 1950s.” The result: “Through decades . . . we’ve seen unions grow weaker and weaker every year while continuing to repeat the same strategic directions.”

Today, less than 6.5% of the private-sector workforce in the United States is unionized, a steady drop from nearly 35% in 1955, 26% in 1975, and 10% in 1995.

To move forward, Rolf has plenty of ideas, including promoting worker ownership and introducing “ethical workplace” certification and labeling programs designed to appeal to socially conscious consumers.