Trial and error
Most learning, especially most organizational learning, occurs through trial and error.
Error occurs whether you want it to or not. Error is difficult to avoid. It's not clear that research or preparation have an enormous impact on error, especially marketing error. Error is clearly not in short supply.
Trial, on the other hand, is quite scarce, especially in some organizations. People mistakenly believe that one way to successfully avoid error is to avoid trial.
We need more trial.