Artemis, the Swedish team, has not decided whether to drop out after its boat capsized during training last month in San Francisco Bay, killing a crew member; Mr. Ellison’s team’s boat was also wrecked when it capsized last fall, though without serious injuries. The teams are considering last-minute changes, including not racing if winds are too high and sturdier helmets and body armor, to improve safety.

And so even before the first race, organizers have begun acknowledging that the design choice for this year’s yacht, known as the AC72, had been a poor one.

“There is no doubt that the AC72 was more expensive to manufacture and prepare for than we anticipated. When you couple that with the economic downturn that we experienced in 2010 and 2011, that’s the reason we have fewer teams participating this summer than we would have liked,” said Stephen Barclay, chief executive of the America’s Cup Event Authority, the company established by Mr. Ellison to run the event, adding, however, that the boats are safe.

In San Francisco, an increasingly unaffordable city where critics say the booming tech industry has been coddled at the expense of the less affluent, criticism has been rising. Much of it has been leveled at Mr. Ellison, who recently appeared at a red-carpet premiere of “The Wind Gods,” a laudatory documentary about his 2010 victory that was produced by his son, David.

“Larry Ellison made the event so big that it made it really difficult for people to put teams out,” said John Avalos, a member of the Board of Supervisors. “Maybe it’s going to result in Larry Ellison winning by default.”

Mr. Avalos, who voted for the event but now says its promoters’ claims “weren’t true or exaggerated,” recently led a hearing on the race’s economic impact. Because the number of teams had fallen to four from the organizers’ prediction of 15 in 2010, the Bay Area Council Economic Institute estimated that the event would generate $900 million in economic activity, compared with an earlier projection of $1.4 billion; attract 2 million spectators, instead of 2.7 million; and bring 6,500 jobs instead of 8,800.