I have never taken a narcotic drug (unless you count the weakest possible prescription, three or four days post-wisdom tooth removal). My daily expenditure in continuing to not take narcotic drugs is consequently next to zilch.
If by that you mean that you've never over-indulged on food, and thus never got used to thinking that 4 slices of pizza in one thinking is the norm, then you're right. It's much harder to give up snacking every time you sit in front of the tv once it becomes a habit than it is to just never gain that habit in the first place, for example.
As I see this it's nothing short of a human tragedy that so many people—in an otherwise wealthy society—got themselves into this adverse metabolic state in the first place
It's not an adverse metabolic state. When you study the metabolism of two different people at the same height and waste, and take the absolute lowest range and compare it to the absolute highest range, the difference is no more than 250 kcals. That's less than two glasses of coke, which most people will drink during dinner. Drink water instead and you just made up for being at the low end of metabolism for your size. You can even compare yourself to body builders. An extra pound of lean muscle only gains you an extra 9 kcals a day in expenditure, on average.
The cause of obesity is exactly the fact we're a wealthy society. Food isn't scarce. I don't have to count calories because my metabolism sucks. I have to count calories because over the course of a day I'll be offered free sodas, somebody will bring doughnuts to work, we'll go grab a burger for lunch at a place where the burger plus a side of fries by itself can have more calories than I need for an entire day (it's pretty easy to get a 2,000 kcals lunch in this society.
It's fine. The food is tasty. I don't deny myself those. But if I have a 4,000 calories worth of food today because I've splurged, I make note of it so I make it up by eating ~350 calories less a day for the next days to make up for it. You can't eat double your calories every single day and expect not to gain weight, but in today's society that is extremely easy to do without paying attention.
It's also really easy to overestimate how many calories you need. I need about 2,000 a day to maintain my weight, which is what people think of as the standard for males. But I'm 5'10", 150 lbs. I don't spend that much just living and sitting at my chair in the office. I spend that much because I also work out every day, and I'm either running for 4 miles or swimming laps for 30 minutes or doing the stationary bike for an hour....otherwise, I'd need to eat about 1400-1500 calories to maintain. If you're not active, it's unlikely you should be eating 2,000 kcals. People don't realize our work changed. We used to have to walk to work, and to be on our feet all day long. My job is sitting all day I'm spending less calories and have easier access to more calories, and people are surprised average weight goes up?
Finally, people think there exist people who can eat whatever they want and not gain weight, because you might see me eat that 2,000 calorie lunch when you go out to eat with me, every time. You think that's representative, and you don't realize you have no idea what I"m eating for dinner, what I ate for breakfast, and what I'll eat the next days when I'm not meeting you for lunch. People who are thin simply don't eat as many calories and / or spend more than you. That's it. Metabolic differences exist, but that's peanuts compared to the real issues.
Not everyone needs to count calories, but those that don't simply aren't tempted by food as much, don't regularly snack, and normally gravitate to less calorie dense foods so they're getting less calories in the first place. If you're the guy always wondering, "should I get the fries today, or am I better off not getting a side", you need to count calories in order to actually answer that question. Have the fries and enjoy yourself, just do so responsibly (if you care about your weight. If you don't mind being overweight it's your life, and I have no right nor do I care to tell you can't choose to eat more because you'd rather do that than be in shape. You simply should understand that's the choice you're making and be free to do whatever makes you happy).