There are different levels of accomplishment in business that can lead to success. The first level is to "know your stuff," to develop an expertise. The next level occurs when other people find out about it.
Many professionals spend their time refining their skills and getting better at their crafts. They take continuing education classes, sit in on demonstrations and do extensive research in their fields. But if a measurable amount of time is not spent letting others know, it could just turn out to be a waste of their time and talent.
That's where marketing comes in. Some professionals don't feel that marketing is necessary. If they are good at what they do, the reasoning goes, people will just know. But frankly, if we don't find a way to better promote what we do and get others talking about the benefits we can provide, the people who need what we offer will likely never know about us.