LOS ANGELES — From the 73-story skyscraper that just broke ground downtown (the tallest in the West), to the blizzard of office, shopping and apartment complexes rising from there to the Pacific, construction is bustling in Los Angeles. Home prices are up, and the foreclosure rate is declining. Crime is down. There is a new mayor in City Hall. In many ways, Los Angeles, like many once-beleaguered cities across the nation, seems on the upswing.

Yet at this presumed moment of promise and potential, Los Angeles is enduring a series of blows that have challenged its self-esteem and even its long-term stability. Some appear more symbolic, like the departure of “The Tonight Show” for New York, followed by the plaintive appeal by Mayor Eric M. Garcetti that CBS move “The Late Show” to Los Angeles when David Letterman retires next year. Others are beyond its control, such as the disconcerting wave of earthquakes that have rumbled the region in recent weeks, reminding residents of how unprepared Southern California is for a cataclysmic temblor.

But the most worrisome blow by far is a scathing verdict on Los Angeles’s civic health that was delivered in a one-two punch — the second on Wednesday — by a committee of lawyers, developers, labor leaders and former elected officials who make up something of the Old Guard here. The Los Angeles 2020 Commission presented a catalog of failings that it said were a unique burden to the city: widespread poverty and job stagnation, huge municipal pension obligations, a struggling port and tourism industry and paralyzing traffic that would not be eased even with a continuing multibillion-dollar mass transit initiative.

Their conclusions amounted to an indictment of a city and its culture, a place that the commission said was brimming with talent and resources but was nonetheless falling behind other major cities across the globe.