yeah, so. What does that have to do with smoking pot every day vs smoking heroin every day? I think the world would fall apart in either case.
It's pretty difficult for most people to stay high on pot continuously. Four hours by ingesting it, maybe six hours by smoking it if you have several more hits every time you start to come down... for the average person that's just about it. If they doggedly keep trying beyond that they just get lethargic or even sleepy rather than being able to refresh the intoxication. It must have something to do with the need to regenerate endorphins, which is a common issue with some other drugs too.
Most adults can get a good high on grass about once a day and then they have to wait until tomorrow. Children--who knows? Their bodies work differently from ours and so do their minds, which, again, is the reason drugs should be a "rite of passage" like voting and driving and screwing and deciding whether to skip a class.
Yeah, we've all met the fellow who seems to be able to be high all the time--if only because he's so visible. Pick any quality and there are bound to be some one-percenters out there who are way beyond the bell curve.
But I think some of those people just get used to the mood and the attitude and the behavior and have learned how to do it even when they're not stoned. That's hardly remarkable. People discover musical nuances, artistic techniques, ways to have fun with their pets, philosophical insights, sexual tricks, even game strategies, when they're stoned, and they remember how to follow through with them later. So hanging onto behavior that's just plain goofy can't be much of a challenge.
If everyone did Vicodin/hydrocodone/oxycontin every day, I think the results would be the same.
Be careful about generalizing from one class of drugs to another. For a trivial example, would you say the same thing about caffeine? It's a highly psychoactive drug that tens of millions of people take every day and it does indeed change the behavior of a large percentage of them. (And turns me into a maniac.) Has the world gone to hell since Europe discovered coffee, tea and chocolate during its colonial era?
Au contraire, it's been hypothesized that the introduction of coffee to Europe was one of the key changes that led to the Renaissance and Enlightenment.
It's certainly been argued that the widespread use of marijuana played a great role in the slow drift of American (and European) culture away from its previous stereotype of being ready to jump into every war it could reach. Notwithstanding Iraq (and Bush was more of a drunk than a stoner

), foreigners are now complaining that we
didn't send troops into Burma, the Congo, Tibet, Georgia, Darfur, etc.
But to get back to your tirade about the opiates, people this old geezer talked to a few decades ago who remembered when they were legal say you're wrong. A hundred years ago doctors and lawyers took morphine or even heroin regularly and then went out and did their jobs like everybody else. Cocaine was available in drugstores; my grandfather was a pharmacist and he sold it along with clean needles (people didn't snort in those days), clean and carefully measured doses, and instructions, and many professionals shot coke. (Or drank it in their
Coca-cola.)
As I have noted elsewhere, based on the observations of people who were first-hand witnesses in earlier eras (including Prohibition, which "got women going to bars"), most of the problems we attribute to drugs are the second-order effects of their illegality and the predictable phenomena that accrue to a black market and a counterculture.