I'll tell you why. She is trying to turn her constant absence into a meme. Because when it's a meme, you don't take it seriously. It becomes just another in-joke. "Haha that funny shark, there she goes again going a month without streaming, that's our Gura!"

That's exactly the reaction she desires. Any negative feelings you might have had get buried under the meme, the in-joke you have to share with your fellow epic memesters.
All according to her plan. If her behavior is a funny meme, nobody will hold her accountable. If her lack of an explation/excuse IS the meme, that everyone post-ironically accepts because it's a meme, then it becomes impossible to treat it seriously. Any genuine criticisms that anyone might have had get swept under the "That's our Gura! xD there she goes again doing her Gura thing! xD" rug.