many people who are busted for heroin,Oxy, subs even crack have weed on them...you talk to them and they started out with the weed. Sometimes it was weed and booze, but they progressed on. Especially if they have addictive personalities. After awhile weed is pretty boring, then comes the hard shit...
Look at our Tbombz for instance...not for the weed, but for the addictive personality, and look at his descent.
I don't buy slippery slope, 'gateway' reasoning. "Well, he was on that pot." As if 'the pot' led to every mishap since. Seems like a great way to avoid having to think about why someone would be so interested in getting wasted in the first place, which is where the actual causes of drug use lie.
Legalization, if anything, will insulate users from criminal circles where other drugs are at hand and make it less likely that they will 'graduate' to other drugs. More to the point, however, the decision to use a drug - any drug - is up to the individual (adult, using responsibly as with alcohol, etc).
I haven't used an illegal rec drug in 15 years. Tbh I didn't derive much enjoyment from drugs.