Eschewing social media is not a culture in and of itself, anymore than eschewing the telephone or TV is a culture. But it is an attribute that some cultures have. Cultures have to be based around the actual ways they do interact, whether in person meetings via church groups, in person hiking groups, bike riding, falconry, camping, whatever. Similarly many people prefer to use person-to-person communication such as text messages, email, telephone calls, rather than broadcasting an edited version of their own thoughts to the world all the time. To assume that if you are not constantly engaging in this type of one-to-many communication, then you must be absolutely alone is to have serious tunnel vision.