If you learn through mistakes, then it follows that you cease to learn when you stop making mistakes. If that is entirely through, wouldn't that be odd? We all know that we continue to learn even though we get better at avoiding mistakes.
Mistakes are effective in making us understand and remember where we went wrong. But it could be a costly way. That is why we learn through OTHER people's mistakes. That is why people are paid for their experience; so that you don't have to pay the full price.