I heard another piece of advice several years ago and found it to be SO true. A Best Selling Author is not necessarily a "best writing author." If we want to sell our books, we should study aspects of sales, marketing, publicity, and promotion or have someone in our camp who does. I personally know writers who could write circles around me AND half the "Best Sellers" list. But not every self published author has a staff. Sales and marketing gives authors an audience; honing craft gives style, versatility, and longevity. We need to cover the spectrum.
I was a Business major in college but studied the craft of writing independently at the public library, and then later, workshops; and then fellowships and major writing/arts grants; and networks AND business networks. I extended myself by lending a helping hand through volunteerism. I recently won an award for fiction and was also named NYCHA/NAACP New York City literacy ambassador. But for many years, I was a hermit who stayed at home, wrote in secret, and only shared my gift with those close to me.
My best friend Karen had to speak some sense into me. She said, "It's not who you know, it's who knows you. You could know everybody, but if folks don't know who you are, what you do and how well you do it, they won't care or give you the time of day."
By the time, I was able to receive and absorb this advice, talent-wise I was overripe fruit. I had been studying the craft for years and years and years, so doors just seemed to magically open. But for many, many years, I was that quiet, inquisitive girl in all the workshops, at all the readings and book fairs, walking with the journal and pencil in my hand jotting details, and with that Titanium flashdrive around my neck, because the makings of an entire publishing company was on it.