> the only books I ever hear about from a marketing standpoint
I'm actually pushing my novel via Taboola at the moment. It's definitively not profitable in terms of sales of a single book, but interestingly in terms of signups to my e-mail list it's one of the best I've found, and I'm spending a tiny amount on it each month on the theory that I'm reaching users who are less jaded and more likely to be outside of the typical bubble I reach on e.g. twitter, and who might well turn out to be worthwhile to be able to repeatedly market to over time in the hope of seeding some word of mouth outside of my normal audience.
Half the fun for me (this is a hobby) is trying to figure out the marketing channels that will work...
However expanding the niche would be a good thing.
But you're right - the only books I ever hear about from a marketing standpoint are the ones my wife is reading for her book club. So either Oprah talked about it, or it's part of the "book club marketing machine" or whatever.
I wish the publishing industry could turn things around. I think the low percentage of people who actively read fiction is ultimately a bad thing. Binge watching Netflix is not the same as binge reading a good book series imo.