As always, it depends. While I agree wrt marijuana, everyone would be an opiate addict if poppy wasn't regulated - it's just that good.
That doesn't match my experience at all.
Hell, Billie holiday suffered from addiction but that bastard Harry Anslinger ordered doctors to not treat her and not provide her with methadone. She died with police stationed at her hospital room door. The FBI also harassed her over songs about lynching.
Nixon is literally on tape saying to go after weed and heroin more harshly as an excuse to arrest more anti-war protesters and civil rights protestors.
I'd argue "cracking down" has done little for controlling drug abuse and has primarily been a method for selective policing. Particularly in the states.
We as a society somehow keep making the whole opiate addiction thing worse with increasingly stronger versions. I've read that Heroin overall was a much more enjoyable drug, and harder to OD on. Then Opioids became big, the sackler family got rich, and now you just have a super cheap, super strong drug that isn't even enjoyable. Fentanyl just knocks you out and makes overdosing easier.
I do wonder what a safety minded policy around opioids could look like, as they're not exactly a new problem in the scheme of human history.
There should be some exceptions, like banning invasive species, but in general, you're absolutely right.
You could get pulled over with a brick of asbestos in your trunk in all 50 states and not have problems. And this was true 20yr ago as well. The regulations around asbestos are/were primarily restrict commercial manufacture, processing and interacting with it so I suppose they could contrive to get you for "processing" if you consumed it.