Will write for dollars

I searched for three recent authors I read online and discovered that none of them have an active social media presence. I'm not sure what this tells me. Yes, you can have an active social media presence and be creatively productive. Many people do it. But, many more seem to be focused simply on the work. Their updates happen when new books pop up on the shelves at the bookstore or the library.

Is this a paywall of sorts? Why give it away for free when you can sell it? Sadly, these three writers were discovered in the dollar store so I am not sure that the strategy is working well for them.