You wrote:
“At one time, San Francisco was one of the most beautiful, engaging cities in the world.”
From WIKI, this describes the turn of the last century in the city by the bay:
[”The Barbary Coast is the haunt of the low and the vile of every kind. The petty thief, the house burglar, the tramp, the whoremonger, lewd women, cutthroats, murderers, all are found here. Dance-halls and concert-saloons, where blear-eyed men and faded women drink vile liquor, smoke offensive tobacco, engage in vulgar conduct, sing obscene songs and say and do everything to heap upon themselves more degradation, are numerous. Low gambling houses, thronged with riot-loving rowdies, in all stages of intoxication, are there. Opium dens, where heathen Chinese and God-forsaken men and women are sprawled in miscellaneous confusion, disgustingly drowsy or completely overcome, are there. Licentiousness, debauchery, pollution, loathsome disease, insanity from dissipation, misery, poverty, wealth, profanity, blasphemy, and death, are there. And Hell, yawning to receive the putrid mass, is there also.”
The Barbary Coast rose from the massive infusion of treasure-seeking argonauts during the Gold Rush. Men from Europe, Asia, South America, Australia and the eastern United States sailed into San Francisco Bay bound for the Mother Lode, many only staying in the gold fields briefly before returning to San Francisco broke or with tiny leather sacks of nuggets and gold dust.
At the end of 1849, out of a population of between 20,000 and 25,000, only about 300 were women and an estimated almost two-thirds of those were prostitutes. Miners, sailors, and sojourners hungry for female companionship and bawdy entertainment continued to stream into San Francisco in the 1850s and 60s becoming the Barbary Coast’s primary clientèle. As the city exploded with the new arrivals, some with shady pasts, soon a wide variety of land sharks, con artists, pimps, and prostitutes staked out an area designed to pluck the gold and silver from the pockets of men through liquor, lust, laudanum-laced libations, or just a hard knock on the head.
Sailors in particular had cause to dread the area because the art of shanghaiing was perfected. Many a sailor woke up after a night’s leave to find himself unexpectedly on another ship bound for some faraway port. When there was a shortage of sailors for departing ships any able-bodied man who wandered into the wrong saloon, or drank with the wrong companion, could wake up with a mysterious hangover onboard a ship. Crime in the streets and corruption in the government offices plagued San Francisco in the 1850s.
Nearly all drinking and dancing establishments in the area were destroyed in the fire that followed the 1906 earthquake, but within months a dozen or so were rebuilt and back in business. Upon the ouster of Eugene Schmitz from the mayor’s office and following the P. H. McCarthy administration, the election of James Rolph Jr, the demise the Barbary coast as a vice zone picked up steam. Between the 1913 anti-vice campaigns led by the San Francisco Examiner and the passage of the 1917 Red-light Abatement Act, the Barbary Coast was effectively diminished and vice activities hidden from view. In 1917 the San Francisco Police blockaded the neighborhood and evicted the prostitutes]
San Francisco went “clean” for a short period (1917-1967) due to a combination of upper class folks worried about “property values” and uptight lower middle class Irish Catholic voters worried about “losing their daughters.”