I've seen about a dozen fights in my life and they all have one thing in common: the winner is stronger than the loser. He may not be bigger, necessarily, but he is always much more athletic. The fight is usually a series of uncoordinated punches, it has much more in common with a boxing bout than a martial arts contest. The winner either lands more punches than the loser, hits them in the right spot that knocks them out, or just makes the other guy retreat. I don't care how many years you've learned how to do an armbar, if Mike Tyson gets a good punch on you, you're out.
The story of a hero who's trained under a master of an ancient fighting style defeating a villain despite the odds being stacked against them is just that, a story. Just because your "sensei," "master," "sifu," "guru," or whatever seems like a smart individual, in reality he's just a scammer. See, assuring people that they can beat up anyone in a fight is in reality a very simple confidence scam. If they're a really good scammer, they can even convince you that you can manipulate your "life energy," "chi," or "qi." This takes a quick moment of critical thought to debunk: "if I'm using my life force to create an invisible punch, am I killing myself?"
Yet, thousands of people sign up to learn how to beat people up. These "classes" can cost anywhere from $10 a month to hundreds or even thousands. You want to win every fight you're in? Sign up at the gym and work out every day. Thinking that you can pay a fee and instantly become Bruce Lee is both ridiculous and hilarious. I can understand what's appealing about martial arts, but it's just false promises like any other scam.