As you see in the comments here lots of people have no idea what marketing is beyond promotion. Unfortunately it's often engineers who are the clueless ones and just think that you just need to build a great product and the sales will come automatically. When businesses started by engineers often fail because they make something that has no product market fit because they skipped the crucial steps of marketing. Engineers often look down on MBAs and think an MBA is useless but in my opinion every engineer should take a business and marketing course.