For me, selling books is a minor consideration compared to the ability to reach people. I think this is especially important when your book conveys a message about which you are passionate.
Perhaps at the end of the day, it is still quality that trumps quantity. I do not mean to sound hypocritical of course, book sales are a wonderful thing. The number of books sold is directly related to the messages sent, but every person who reads and absorbs the true meaning of the book is like a speck of gold to an author.
I am so grateful for each reader, each response and embrace each one. I imagine that is what keeps writers writing, that special connection to the reader, for that is truly a connection to the universe.
Have a blessed day.