Before glp's broke into the vernacular, my cousin was on one. I remember he said to me that he wished he had titrated up more slowly instead of "blindly" (his language) increasing every 4 weeks. He ran out of runway and still had weight he wanted to lose. He felt very frustrated. I don't know what he ultimately decided to do. But his frustration stuck with me.
This is why I lean conservatively on this topic.
There are now many ways to work around a lack of runway. 4 yrs ago, I don't know what approved tools he had at his disposal to compensate for reaching approved ceiling dosage.
I think this way of seeing how GLP's work is based on internet folklore, not the underlying research. There is no evidence that how quickly you increase doses makes any difference to the final amount of weight loss, just the final dose. Increasing slowly is entirely about reducing unpleasant side effects, suddenly starting at max doses would be enough to put a decent percentage of people in hospital with intractable vomiting, so avoiding that and making the experience less unpleasant makes a lot of sense. Equally folklore based is the concept of starting on one less effective GLP so you can switch to a more effective one later once you stop losing weight. It just does not make any sense at all, pick the most effective drug or the one with the least side effects. I cannot see any good reason to use semaglutide currently, given it has more side effects and is less effective.
I think the reason people feel that they "ran out of runway" is just expecting GLP's to work miracles. There is a limit to how much weight people usually lose on them, and a lot of people with more severe obesity have more to lose than these drugs can achieve. And exactly 50% of people are going to lose less than the average amount of weight lost in the trials, and some unlucky people are going to lose a lot less, and a few lucky ones a lot more.
The amounts of weight lost I see on this forum are often higher than the results seen in the studies, and I think it is mainly selection bias, the people who had amazing life changing results are the ones most likely to post and keep talking about it.
People who are at a genuine plateau, that is on maximum standard dose and stuck there for a month or more are just at the limit of what that drug can do for them, and I think it is super important to accept that and stay on it as any significant weight loss will improve health, even if you are not at completely non overweight BMI's. Before GLP's doctors were very happy to claim 5 or sometimes 10% weight loss maintained as a major success, with significant reductions in long term health risks.
There are no proven methods yet to fix this problem, that have actual studies showing that it is safe, but anecdotal reports demonstrate that combining GLP's or increased doses can work, hopefully future research shows that the health benefits outweigh the risks of using unstudied therapies.