Some things require talent like your examples, weight loss does not imho. The disparities in obesity and culture within country says it all.
The ability to be disciplined about eating is also a talent.
Or do you think that somehow genetics don't play one of the largest roles in your ability to be disciplined when it comes to food?
You just have to be disciplined to always shoot accurately at the basket. Most people send it one way or the other but if you are disciplined enough in your aim at the basket no matter the constraints you will be the best basketballer of all time.
Weight loss of course is helped by talent, because genetics are talent.
Metabolisms fluctuate, although granted not by much. But what really varies is your response to food. And it's not just genetics. It's food scarcity, early childhood, your environment.
The (maybe) sad reality is that there will be people skinnier than you will ever be who have put in zero effort. Nada. That's life. Just like there's people who can sing better than me off the rip and I took vocal lessons for 10 years. Life's not fair.
But the bright side is, I can drink and not be an alcoholic. Maybe they're just lazy or something. Or, maybe this mentality is one people feed themselves (ha) to feel better about the circumstances of their life.
Wouldn't we all like to believe we're the way we are because we're strong, brave, and hard-working?