After thanking my friend, a friend of his then said that being versatile meant I was shallow because I didn't go deep into a genre.
The comment made little difference to me -even though at the time I wasn't selling well - as my versatility has meant I rarely get Writer's block. If I do get stuck, it's more likely personal than by a lack of ideas. I often say "I suffer from the opposite of a block." I have so many ideas, I needed to create a file to store them.