Gutter punk kids & NOPD are a joke
It's not true.
It is much cheaper in places like Chicago, NYC, NJ, Philly, etc.
And the majority NO's heroin comes from Colombia/Mexico just like the rest of the country.
You are wrong and there are books if you want to do your own research. Junky, Dreamland, etc.
When the mob fled to New Orleans they started getting heroin off the docks from the Vietnamese fishermen. New York was the only other place the Mob used the Vietnamese to import heroin. That is why New Orleans has a long history of heroin and cultural heroin tolerance.
Have you ever read a single jazz autobiography? Do you know where all the N.O. Jazz musicians got their heroin? Do you know why William Burroughs in Junky lived in New Orleans instead of L.A. which is much closer to Mexico?
New Orleans has not seen a real influx of Mexican gangs to even bring in Mexican heroin. Most of the Mexican heroin we get is from rural Mexican towns making batch heroin and bringing it in.
The Mexican heroin started showing up in New Orleans in the 90s, just like everywhere else in the country.
After Katrina, the Mexican heroin really pushed it's way through into the city.
Local cops say heroin's resurgence is worse in New Orleans right now than in other areas of the country. They attribute the drug's prevalence here to Hurricane Katrina shaking up local drug distribution networks.
  "Prior to Katrina, there were very few conduits bringing in heroin from Houston," says Capt. Bruce Little of the New Orleans Police Department's Specialized Investigations Division. "Post-Katrina, there were a lot more people with a direct pipeline. Now the problem is that the heroin hasn't been stepped on as much, so the purity is much higher and users have no idea of how potent it is."
  Retired FBI Special Agent in Charge James Bernazzani, who led the bureau's New Orleans office after Katrina, says the market was flooded with cheap, potent heroin as new dealers tried to gain a foothold in the market. "This very potent Mexican heroin didn't discriminate between white or black, gay, straight, uptown, downtown, or by age," he says.
  A new heroin user in New Orleans can now get high for hours for just $5. A "20-bag," or $20 worth of heroin, is enough to get a new user high for two days, Rahman says.
But to answer the OP's question, the gutter punks are here because New Orleans is one of the 4 major heroin cities in the U.S. because the Italian mob already had the contacts to import heroin when they fled here. So here, heroin has a long culture. It is part of the city, part of people's lives and has been since the beatniks and black and white television. Jazz, man.
All of this makes New Orleans a cultural tolerant heroin city, hence the gutter punks.
Now as far as America's opioid problem and all of the new heroin here post 90s, then really post katrina, we are in the same boat as the rest of the country. The only difference is heroin is stronger here because there is a cultural tradition of clean white asian heroin (china white). Currently, the rest of the country tries to emulate New Orleans and New York heroin by cutting the brown heroin with fent (which is white) and naming it China White. But this is not the same as original China White of lure, that I am sure we have all heard of before. White, clean heroin is specific to New York and New Orleans because it DID NOT COME FROM MEXICO, where even the fancy Mexican heroin is brown (brown sugar) or black tar.
Here is a junky to clear it up for you.
And also, the chaces of getting china white or afganhi white on the west coast is just about impossible, because it come from either of those two contries it is shipped to the East coast, West coast gets tar because its made in mexico, so vice versa, east coast cant get tar.
But who would want tar, cuz you can still get brown sugar which is about 8x more potent than average tar.