I agree with Susan.
While I'm not a book club member - or even aficionado - I find almost all my reads from recommendations from fellow readers.
Not ads. Not algorithms. People.
I *only* read self-published books but manage to find enough to read 2-3 books a week and only very, very rarely run out of something to read.
I think there might be a confounding issue involving how many books I read.
Heavy readers can't get enough books from the algorithms.