LOS ANGELES — The roughly $19 million spent in the 2013 mayoral primary here made it the most expensive on record. But that is not the number that has people agog. Just 21 percent of registered voters turned out for last week’s election — the lowest rate for a primary without an incumbent since at least 1978.

The paltry showing has many here wringing their hands, wondering what has become of the city’s residents. Is there no such thing as civic engagement in this sprawling metropolis? Are municipal elections really that boring, even as the city faces serious financial problems? After many here thought the stereotype of a vapid city was buried long ago, there is a renewed sense of a civic inferiority complex.

“I am in mourning,” said Steve Soboroff, who ran for mayor in 2001 and received more votes than any of the candidates in Tuesday’s election did. “The idea that it is socially acceptable not to vote, but people talk about where they get their shoes from, is shameful. I love L.A., and I am very proud of our city, but people here need to get a grip.”

Much of the post-mortem over the primary, which sent two City Hall insiders to a May 21 runoff, has focused on the turnout. Newspaper editorials and blogs have called the numbers “pathetic,” “embarrassing” and “stunning”; one columnist said they “redefined apathy.”