I think I can both agree and disagree with you. I too started writing at a very young age. I was writing novels as a preteen—none of which were really that good, but I was certainly a stronger writer than most people my age. I was told I had talent, but I must report that talent has gotten me that far. In fact, I think being told I was talented at an early age made me lazy and less ambitious. I'm trying to unlearn this "talent trap" now as a working adult and see writing for what it is: a job with skills that constantly need to be upgraded.
It's true that many great writers didn't study writing their whole lives, and maybe some god-given talent has something to do with it, and maybe not. Maybe as outsiders to a new craft, they studied it seriously from the ground up. Maybe something from their other career really boosted their sense of story; after all, the best writer can't write a detective story the same way as an ex-detective, right? Anyway, I don't necessarily disagree with you, but I would politely not agree with you 100% on everything either.