The enthusiasm for revising the legal status of pot around the country has for the most part obscured any debate about consequences to public health. That pot is regarded as relatively harmless is troubling, because much of what we know about it is based on studies conducted nearly 50 years ago at a time when what was consumed was much less potent than it is now.

Within the academic community, Jonathan P. Caulkins, a professor of public policy at Carnegie Mellon, has been a leading voice warning of marijuana’s attendant dangers. As he has put it, beyond the fact that pot use has been correlated with a wide variety of negative outcomes in terms of physical and mental health, the real issue is that more than half of marijuana is consumed by people who are high more than half of all their waking hours. Pot shouldn’t be dismissed simply because it won’t kill you.

Mr. Caulkins’s research also shows us who is likely to bear these health burdens to a disproportionate degree — and it is not snowboarders in Vail. Looking at a decade’s worth of federal surveys on drug use, he and a partner determined that Americans with a household income of less than $20,000 accounted for close to 30 percent of all marijuana use, even though they make up less than 20 percent of the population.

One fantasy that advocates of legalization have is that changes in the law will energize a redistribution of wealth, not only because tax revenue from pot sales can be funneled to various worthy causes but also because the poor will reap new entrepreneurial opportunities — in every neighborhood a Stringer Bell.

Mr. de Blasio has made a big point of saying that a legalized pot industry should not be overly corporate, and that retailers in parts of the city that have been so adversely affected by punishing drug laws get licenses and the chance to make money. But this is the same mayor, who during five years of presiding over the city, has been wholly unable to stop the onslaught of chain stores in New York, wholly unable to preserve the fortunes of a longstanding local merchant class.

I asked Mark Kleiman, of the Marron Institute at New York University and one of the most sought-after experts on drug policy in the country, what the future looked like. He foresaw a world in which pot, legal in ever more states and eventually at the national level, will get cheaper and cheaper. The expected tax windfalls would become less likely, unless pot is taxed at the level of potency rather than sale price. The trend toward vaping means there will be greater demand for oil, and if you can melt everything down for oil, pot will be less expensive to produce, because at that point you can grow it like corn.

“You can produce all the intoxicant used in a year on 40,000 acres,’’ Mr. Kleiman said. “That’s 20 family farms in Iowa.” Eventually a joint could cost a nickel; Nabisco will take over edibles. “You will have pot grown in Iowa, processed by Cargill and sold by Amazon,” Mr. Kleiman said. “No one will make money except Jeff Bezos, who always makes money.”