I feel that you are so right when you say that being a salesperson is a job that requires skill. And talent. Salespeople have a very particular set of skills that in today's society seems to be disregarded. As a person who spends her life as a customer I can assure you that I do not know, 90% of the time, what my precise needs are. I go to request services with a very vague image of what I need. And the salesperson is stuck there, trying to understand what it is that he can do for me.
The same goes for advertising one's work. You do not really know what the readers wish and the readers often do not know what they would like to see and read either. How many times as readers have we stumbled across a great work without knowing that we would like it? And how many times as readers have we truly dedicated a chunk of time to write down our likes and requirements for what we consider to be good work.
It is tough to advertise. The readers are a black box. And here we are, taking wild guesses about what it is that that black box wants. Supposedly, if one were to do a multiple-choice exam without knowing anything and answering all questions my chance, the mark one would get would be about 25%. I wonder whether the same applies to advertisement. You go in there, trying something and hoping chance will be on your side.
And the result is 25%. Ouch.