Just recently got into boxing and it seems to have a pretty narrow learning curve compared to the other sports/martial arts I did (wrestling, judo). Boxing is extremely extremely intricate with the smallest movements but the fundamentals are simple. It seems that a guy could go into boxing in his 20's or so and still have a good chance at being successful at it and reaching the top. Stamina, natural timing/reflexes, etc. could possibly overcome technique. This differs from say wrestling where you're pretty much gonna get f'ed in the A if you start anywhere past freshman year of high school because of all the techniques used that others have already got down in elementary. Discuss.
What is there to discuss? As with anything learned it always comes down to the practitioner and their ability.
Having moved from boxing to grappling... Boxing is a lot simpler to learn the basics... Getting good is another thing!
The basics are simple. Three punches and a few different methods of defence for each. Then there's movement, ring intelligence, etc. It still takes a pretty special athlete to start late and end up anywhere near the top. Stamina and timing can not overcome technique. Because at the top you'll meet someone who has stamina, timing and technique.
In fact you'll meet those people far below the top as well. Perhaps you should try reaching the top of your district first, you may have to reevaluate your theory. Seeing that you're from Cali, I think you'd be in for a large amount of very painful surprises.
Look at Mayfield for instance. Plenty of athleticism and stamina, but as soon as he gets in with a schooled fighter like Garcia for instance, he will be a highlight reel KO victim. EDIT: I just checked his post history. This kid is a troll. He probably never stepped foot in a boxing ring.