The companies that are the prime purchasers of computer software will not buy a software package if the costs of training staff to use it are high, and we know that it is expensive to teach people a software package that demands the memorization of unfamiliar commands. As a result, to be successful, commercial computer software cannot require users to memorize unfamiliar commands.
The conclusion above follows logically if the assumption that if most prime purchasers of computer software buy a software product, that product will be successful is made.