I don't know exactly why she reduced her public profile, but some tragic and strange events preceded it. First her niece disappeared and is presumed dead, then Alex Jones famously made a spectacle of screaming in her face and accusing her of being a deep state agent. She also made some videos at antifa/BLM riots where the audio picked up her voice screaming and sounding very distressed.

So it seems like a lot of personal stress added up to her taking a step back from things. She is active on Twitter though. https://twitter.com/michellemalkin