Don't really think about staying on this for life. Of course I will - same as statins. The time I save not worrying about it goes straight into other stuff.
Not looking good based on SURMOUNT results—people gained a bunch back after stopping and kept gaining. On the flip side, plenty of us here would rather stay on these for life. Way less food noise, better health overall. I'm around calories all day and not being tempted is huge.
food aversions on mounjaro are super common early but soften by dose 2 or 3 for most. bigger thing is electrolytes—you're eating way less volume. diy salt and potassium mix works but tastes awful. salt of the earth made a difference for me when appetite was zero.
The question of whether it's all calorie restriction or the medication doing other things is actually meaningful - there are metabolic effects beyond appetite suppression that contribute to the result. Too tired to work out at the high end of the weight loss and then finding the energy after is the sequence most people experience. The OP's diet-first framing is right - the medication makes the adherence to it sustainable.
The calorie-budget approach that allows occasional higher-calorie foods within the daily total is more sustainable long-term than strict restriction - it removes the guilt cycle that tends to create restrict-then-overeat patterns. Protein and fiber first, and the rest fits within what's left.