Over the past few decades, San Francisco has spent billions of dollars to address homelessness. And yet many residents say the situation on the streets is worse than ever, with tents on sidewalks and people with serious mental illness roaming the streets.

And, with a mayoral election underway, it seems many in this famously tolerant City of St. Francis have finally have run out of patience.

On a recent weekday morning, literally every single voter I talked to said the same thing when asked what was the top issue facing the city: homelessness.

"Walking each day in this neighborhood and seeing everybody sleeping in doorways," says Castro neighborhood resident Linda Zaretsky. "It’s just intolerable, painful and morally wrong."

She has lived in San Francisco for about 30 years and she sees poverty as the fundamental problem. And she says she’d pay more taxes to address it.

Voter Paul Miller also feels compassion, but he’s weary of confronting the issue everywhere he goes.

"No one should live in a city where they walk past people on the street who may or may not be shooting up or dead or needing help," Miller says. "There's no easy solution to homelessness. There's a thousand different problems which create a thousand different stories."

Duboce Triangle resident Abraham Ali is less circumspect, and says he has run out of patience.

"I wanna see results. I wanna see action," Ali says. "Like when you go to the Muni or BART, they're all over -- laying down, doing drugs in front of you, trash everywhere. And if I was a tourist coming to San Francisco, I'd think the whole city is like that. And it's not -- it's a beautiful city."

Joe D’Alessandro, CEO of the San Francisco Convention & Visitors Bureau, has been hearing so many complaints from tourists and convention-goers that he decided to speak out.

"This is the wealthiest major city in the wealthiest state in the wealthiest major country in the world," D'Alessandro says. "And we can't live with the situation on the streets we find ourselves with right now."

Standing near the Powell Street cable car turnaround, D'Alessandro is careful not to blame anyone, including the homeless themselves. "We've just become oblivious to what's happening in the streets."

He notes that tourism is a $10 billion industry in San Francisco, generating $700 million in tax revenue each year. It can't be ignored any longer, he says, and he's pleased that at least all the mayoral candidates are talking about the issue.

"We just want to be sure that there’s some action and it’s not just talk -- that’s there’s really steps being taken," he says.

D'Alessandro admits conditions on the streets are looking better. In recent weeks, Mayor Mark Farrell has moved aggressively to clean up encampments -- raising the bar for whatever the next mayor decides to do. But his actions have riled up homeless activists, who plastered street poles with posters condemning him.

The three leading candidates for mayor are all offering similar plans to deal with homelessness -- and clean up the streets and sidewalks.

Board of Supervisors President London Breed supports so-called safe injection sites so that addicts aren’t shooting up out in the open. At a candidates forum, Breed stressed prevention.

"Many of the folks who are out there on our streets homeless had a house here in San Francisco before they became homeless," Breed said. "We have to make sure that we do everything we can to keep people housed."

To Supervisor Jane Kim, considered by many to be the most liberal candidate, the priority should be more services.

"So we have to invest greatly in supportive housing, more shelters, if we’re really going to address this crisis," Kim said at a candidates forum co-sponsored by KQED.

Former state Sen. Mark Leno released an 11-page plan that calls for ending homelessness by 2020. One of his campaign slogans is "Shake Up City Hall."

"I think the city is out of control in terms of homelessness, housing affordability, condition of our streets -- and I think City Hall has failed us," Leno told KQED.

Before he suddenly died in December, Mayor Ed Lee created a new Department of Homelessness and Supportive Services to coordinate the city’s response to homelessness.

The man in charge of that department, Jeff Kositsky, says things are going in the right direction now -- with many encampments cleaned up and more people connected to shelters and services. He just hopes the next mayor -- whoever it is -- doesn’t disrupt that momentum with too many new initiatives.

"Because if we keep pivoting from shiny object to shiny object, or if we keep panicking and just grasping at these ... we’re not going to get the job done," Kositsky said recently at one of the city's Navigation Centers.