Marketing is more than just advertising and sales
Why is it that the most diverse profession in the world is always associated with only two functions, advertising and sales? Perhaps its ignorance or complexity or a little of both!
Marketing begins with marketing research, the gathering and analysis of data about customer profiles and buying behavior, competitor's capabilities and weaknesses, industry trends, and many more topics.
This input is used to identify problems and create possible solution(s). From there marketing looks at logistics, messaging, value propositions, gap analysis, benefits, technology trends, cost and profit margins, psychological impact, distribution channels, naming, colors, features, ... and on and on.
I think you get the idea. Marketing is the most diverse and thus complex of all professions as it touches every business function in an organization.