I deleted my Facebook in 2014. Got back on a couple of times, just for personal reasons, but I never really used Facebook to connect with fans or market myself and my books.
I've always been skeptical of claims that you NEED social media in order to have an author career. My books started to take off when I was teaching English in a small village in the Caucasus Mountains, where internet access was a 30 minute bus ride away. With only a couple of hours three or four times a week to do everything that I needed to do on the internet, social media was very low on the priority list. And yet, my books continued to sell.
I'm not a huge selling author, but I have managed to build an email list that consistently sells books. Not that that's the only thing I use it for. At this point, I've completely disconnected from all social media except Goodreads and Dissenter (and YouTube, I guess, though I never post comments anymore), and my newsletter now fulfills most of the roles that my blog used to fill. News, writing updates, personal notes, thoughts and reflections, and of course plenty of book deals and other stuff to check out. It seems to be working.