It shouldn't be used for years and years.
It doesn't take long to get results. Once you're in the 3-4 months, you'll probably be at max dosage and you'll shed all types of weight.
Years upon years is ridiculous and I'd guess a small percentage is still on that shyt at that point.
You're right, it shouldn't be, but realistically I'm sure there will be some people using it on and off (lose the weight, gain it back, get back on, lose the weight again, gain it back, get back on it again, etc.) for years and years. Or people who aren't even overweight to using it to try to get shredded or because they have body dysmorphia.
Those types of people will probably fukk up their metabolism and become frail.