Do you actually believe that or is this some sort of rhetorical point? This stretches my suspension of disbelief to be honest.

People can buy very addictive drugs from pharmacists (legal drugs are a huge contributor to the opioid epidemic), and there were doctors in some areas that were known for being extremely lax about that sort of thing.

Lots of the illegal drug dealers do sell really harmful stuff. But before it was legalized they sold weed…

We should not pretend our laws are perfect, they are always undergoing refinement.

Disagree. Someone who is well and truly addicted to drugs does, in fact, need it like the air they breathe. Drug dealers provide a necessary service to those folks where a lot (most?) of the "above the belt" services aimed at rehabilitation either fail completely or make matters actively worse.

There is a huge difference between a regulated and controlled system and your neighborhood methhead mixing up something in his kitchen to sell to the kids a couple of blocks over