What societal problems do we have as holdovers from Prohibition, and how many have disappeared?
Systemic societal problems from prohibition are generally gone now, I'll grant you that one
I'd say getting rid of the mafia, or other gangs in charge of the illegal alcohol trade, was a huge plus. This is the same era/group that gave us drive-by shootings & the first national gun control law. (OK, there's a big negative.)
And the mafia gained in power long after prohibition ended, when booze was no longer the big selling point they moved into protection rackets and narcotics and prostitution, there is always new criminal endeavours to enter for the illegal business.
Ditto for losing the low-quality & sometimes dangerous / deadly things people passed off as drinking alcohol. Knowing the composition & purity of what you're ingesting / inhaling / injecting is a huge plus.
Alcohol is fundementally different the crack cocaine or ecstasy, or methamphetamine. especially ectasy and the designer drugs, there is no way I can see that pure or regulated ingrediants would make it less dangerous in the least. Alcohol is only an issue if ingested in large enough amounts, alcoholism doesn't form as quick as addictions to other narcotics do, alcohol has long standing use for both ceremony and traditionally acoholic beverages were used to store excess grain or to make water safe to drink in places where it was often contaminated. crack cocaine and ecstasy, et al have no ceremonial significance, and in no way aid one's general health in any way, furthermore even small amounts can cause major health consequences and addiction that can only be combated by pharmaceuticals quickly forms with one or two "hits" there is no comparison between hard drugs and alcohol.
People who drink too much at once, or as a habit, can get treatment without worrying that they'll be put in jail simply for their drug use
in Washington state at least, drug rehab is considered medical care and is thus subject to state and federal privacy protections. furthermore in Washington drug addiction is considered a "disability" if one voluntarily seeks medical treatment or counseling for addiciton and employers must reasonably accomodate rehab or addiciton counseling by their employees or risk fines from the WA Human Rights Commision. I don't know what WI says about that or any other state, but I'd have to imagine more states then just WA have that standard. You will not be jailed or fired from your work in this state if you seek counseling or medical rehab and haven't been caught by testing or police.
And the gov't makes money from taxing now-legal products.
If such products are sold retail. Right now a fight is raging in this state over pharmacies being required to stock birth control pills, are we going to require pharmacists to stock ectasy or crack hits? most reputable pharmacies are in the business to stock medicine, not recreational narcotics. I have to imagine most pharamcists would want nothing to do with the type of clientelle that would buy such drugs. even marijuana is controversial enough that access could limited. if that's the case the illicit networks to distribute will remain, except now they only get charged with not having proper licenses. unless retail outlets adopt selling controversial drugs with no medical purpose then the state's tax revenue will be limited.
IMO, all of those would apply to other drugs (currently illegal).
IMO it's not the same thing.