Andrew Yang asked a rhetorical question to his San Francisco presidential campaign rally audience Sunday on a subject that was on everyone’s minds: Why are wildfires and shut-offs happening in the most technologically advanced country in the world?

The answer, Yang said, “are four words: P, G and E. I think those are technically words. A letter is a word, actually, when you do it like that,” he quipped, as he often did in a 50-minute speech that veered from wonky policy proposals to extemporaneous one-liners.

Then Yang, who has shocked the keepers of conventional wisdom with the endurance and growth of his campaign, turned serious about Pacific Gas and Electric Co.

“But PG&E is an emblem,” Yang said. “We know exactly what their incentives are: Their incentives are to cut corners and try and make as much money as possible for their shareholders.”

The crowd booed.

“You cut corners long enough, and then we all pay the price,” Yang said. “That is an emblem of what is happening in our country today. Everything revolves around the almighty dollar. If you’re a PG&E executive, you don’t get paid based upon our well-being. You get paid based on whether you can cut corners successfully enough to add another couple dimes to the bottom line.”

But the utility isn’t the only problem, Yang said. He promised to quadruple the budget for the U.S. Forest Service to better clean up forests that have become “tinderboxes” because of climate change.

“This is an emblem of what’s gone wrong in the United States,” Yang said. “Our government has failed, capitalism is failing us, and it’s up to us to do better.”

Organizers and some attendees said the wildfires, blackouts and evacuations around the Bay Area dampened the turnout for Sunday’s rally. The campaign estimated the crowd at 2,500 people as the audience filled roughly half of the middle part of Civic Center Plaza in front of City Hall. That’s about half as much as what some organizers expected.

Yet Yang said Sunday that it was his rally in March in San Francisco that drew 3,000 people that convinced him that he had tapped into a vein of support. Since then he’s grown beyond being known only for being the candidate proposing to give $1,000 a month to every adult U.S. citizen as universal income.

Now, he has an army of supporters — a.k.a. the Yang Gang — whose level of candidate homage rivals the followers of Sen. Bernie Sanders. They wear hats that say “MATH” for “Make America Think Harder” and raise their “Yang Gang” signs high every time Yang mentions a number or a statistic, a nod to Yang’s nerdy embrace of being “numerate data-driven.”

“I like him because his approach, his reasoning, is data-driven,” said Jason Badua, a 26-year-old from Oakland who was wearing a “MATH” hat. “Even if you disagree with him, you know how he came up with his idea, because he’s all about the data.”

Similarly, Ines Chan likes Yang because he doesn’t try to win over voters with an emotional appeal. Plus, as a longtime customer service worker who until recently was making minimum wage, the idea of a $1,000-a-month basic income is appealing to the San Francisco resident.

“I don’t like hearing politicians shout at each other. That’s not appealing to me,” said Chan, 27. “He doesn’t do that.”

Others are joining them. Yang raised nearly $10 million in the most recent fundraising quarter, almost four times as much as the previous quarter — and more than Sens. Amy Klobuchar and Cory Booker did over that time period.

He has qualified for every debate, yet he is barely mentioned in cable news coverage. He ranks 12th among the candidates in terms of how much the cable news networks are mentioning him, according to the GDELT Project that monitors media — just ahead of Montana Gov. Steve Bullock, who hasn’t qualified for any of the debates.

In the early states, Yang is polling best in New Hampshire, where he has 5% support — higher than Sens. Kamala Harris, Klobuchar and Booker, according to a CBS News/YouGov poll. Overall, he has 2.5% support — sixth overall among the Democrats, according to the RealClearPolitics.com amalgamation of major polls.

An earlier version of this story incorrectly reported what “MATH” stands for on Andrew Yang supporters’ hats.

Joe Garofoli is The San Francisco Chronicle’s senior political writer. Email: jgarofoli@sfchronicle.com Twitter: @joegarofoli