Worthwhile things to wonder about, and it's exactly why this drug class gets labeled a lifelong medication for people dealing with metabolic dysfunction. Eventually the body adjusts to the dose, yet remaining on it can pin the body at that new baseline anyway. That's actually further proof the medication itself isn't wearing off, it's the body doing the shifting.
Could we push the amount upward without limit, that edge might last longer, though sooner or later every weight-loss method loses steam. Seems like the body carries some sort of built-in override once whatever keeps that baseline in place gives out.
There's actually some interesting research pointing toward that baseline being resettable for certain people after around three years. Meaning these might not have to be permanent prescriptions for everyone, provided someone locks in solid lifestyle habits and settles on the right maintenance amount to hold across that three-year stretch... then sustains those habits going forward.