I'm sure you aren't trying to come across as fat shaming, but the reality is of course not zero sum. Diet and exercise doesn't magically work for the entire population.
Diet and exercise definitely worked for me but im not willing to be a sample size of 1 in the face of so many others with legitimate stories.
It's so simple, really.
(See the problem here?)
Not drinking is 100% guaranteed to cure alcoholism.
Buying a house is 100% guaranteed to solve homelessness.
It's really that easy.
Except reality is it's hard. Addiction is a real issue, people have underlying compulsions and habits as difficult to break as with physical pressure. For some people monitoring caloric intake isn't the option it is for others.
But you're saying "it is as easy as doing activity x" without concern for the difficulty of that activity. There are a wide variety of reasons some people might get fat, but once you are fat, it is far more difficult to get not-fat than it was to get there in the first place. There are a wide variety of feedback loops within the body, including epigenetic ones, that make it much harder to lose weight and keep it off.
Once upon a time, it was trivial for me to not eat garbage food, or too much of any sort of food. I had more trouble trying to eat enough to be in a large enough caloric surplus to get enough protein in and stay in a large enough caloric surplus to build muscle. I never had "food noise" or anything of that nature. Then life happened, my circumstances changed, and I had less time to worry about food. I spent more time going out with co-workers and friends eating and drinking. Other nights, I was too busy to cook, and ordered in more. My weight went up, and before I really realized it, I had put on significant weight. And I realized that something I had found trivial before, something that had taken zero willpower, that I had never struggled with... was something that was incredibly mentally taxing.
Could I count calories and lose weight? Of course. Could I add exercise back in to my routine? Yep. But it was difficult in a way that I never had understood back when I was fit, in a way that I never would have believed could happen to me. And as soon as I got busy again, or had other things occur in my life that took priority, the mental effort to keep "just counting calories" and push down my food cravings and hunger no longer seemed worth it.
I could exert a huge portion of my willpower on this, struggle with it, remove my capacity to spend more time having care and empathy for others, forcefully deprioritize other things in life... or I could use a GLP-1.
I know which path made sense for me, and it's been a hugely beneficial thing in my life.
Yeah, good luck with that.
GLP-1 agonists reduce your desire for, and for many people, your ability to consume things like “a pint of ice cream three times a day.” That’s kinda the point.
"No free lunch" does not in any sense imply that there are no positive-sum decisions to be made.