Your complaint doesn't seem to be so much with boxing or training... you just found a better trainer for you.

It's an observation that sometimes, the people who win fights don't necessarily have better technique (or at least, the best technique for themself) and get by on talent, guts, perserverence, intuition, etc.

It's an observation that being a champion doesn't mean you can train them, or that if you train champions it doesn't necessarily mean you teach the best technique, or at least, not the best technique for everyone.

Sometimes there are genius coaches out there who just don't get any talented or dedicated pupils to properly apply their methods, and then one finds you, and you discover them, sort of in the same way a coach who's not very good might discover a pupil who is really dedicated and has great intuition and ability to read an opponent, even if the methods they're using against them aren't as good as they could be under a better coach's techniques.