By the numbers
As I and many other authors are finding, it's not easy to gain attention for my novel. As someone who like data and hard numbers, I checked out the competition.
There were about 1 million books published (in the US) by traditional publishing (i.e., a publisher pays the author for the text and then produces it; the author puts in effort, but does not spend his or her own money). However, another 2 to 3 million more books were self-published. Depending upon what source I look at, however, this is a factor of between 2 and 4 times increase over the number of self-published books around 2010.
About 100,000 novels are traditionally published each year, and in recent years about two to three times that are self-published (not including juvenile fiction). So my little novel is competing against 300,000-400,000 over novels.
That's a lot of competition. No wonder it's hard to get traction, even with advertising.
Some of my sources, you can find your own:
https://www.publishersweekly.com/pw/by-topic/industry-news/publisher-news/article/91574-self-publishing-is-thriving-according-to-bowker-report.html
https://www.tonerbuzz.com/blog/how-many-books-are-published-each-year/