How many people fell away from playing numbers because part of the thrill was doing something illicit?
How many people would never start because of that?
Just as with other prohibited items, part of drugs social cachet is their very illicitness.
And besides, it's not a very good analogy, since by creating a state-run lottery, the state of Tennessee started providing a service that was legal and socialy acceptable in many other places around the U.S.
I'd also wager that the drive to acquire drugs to support a chemical dependance habit is a lot stronger than the drive to engage in low stakes - low odds gambling. Just as would be the desire to NOT start.
And while I won't argue that there won't be people who'd try the newly legalized drugs, who might not have before because they were illegal, I'm hard pressed to believe that it would be massive amounts of users who would undermine the "peace diiidend" from legalization.
And then there's the "take it or leave it" factor. There certainly are many, many Americans who've tried pot once or twice, and never formed a habit, much less moved on to other drugs. And in terms of "addictive" narcotics, many more have become addicted to legaly prescribed ones even within "normal" timeframes, and without such things as "doctor shopping", but still manage to quit when the prescription runs out.
This happened to my own wife, post surgery. She became addicted to Oxycontin and Fentanyl. And the latter drug, a synthetic variant of Heroin, is arguably much, much, more potent than anything commonly availible on the street. What was happening was plainly obvious to both of us. The "problems" above and beyond her surgical pain were clear if we missed getting her a dose.
However, when the time was up and the doctors decided she had recovered, she went through withdrawl, and never sought out another source of Fentanyl, Oxycontin, or any other drugs. And this was full DT's, sweats, shakes, nausea, the whole nine yards.
My own wife's experiences are certainly a limited sample size, but it's my belief that there's a cultural and psycological component to addiction, and with any cultural problem, government solutions are hardly ever effective.
And BTW, by accusing me of "making arguments from agnosticism" and offering no hard numbers, or anythign else beyond "anecdotal evidence and reason" to support your contentions, aren't you conversely just defining your own positions on drug prohibition as articles of faith?