The withdrawal symptoms aren't especially serious in the grand scheme of things, but they're still unpleasant enough to discourage people from getting stuck in that 5 - 20x per week range.
With all the perverse incentives in play, I'd sooner trust the TSA's numbers for how many terrorists there are with long fingernails.
"Addiction isn't a problem" is the biggest myth perpetuated in the smoking community. I'm not trying to make pot out to be any more or less monstrous than it is, but to claim that addiction isn't something that happens is to hide one's head in the sand.
A lot of people are forced to (or "elect" to) mandatory drug treatment/counseling as an alternative to harsher sentencing for first-time marijuana offenses.
Success rates are obviously low for these, for the same reasons that requiring all college students who ever drink alcohol to attend AA meetings would have low "success" rates.
You can't assume all people who attend drug treatment actually have a drug problem.