The reason why Demna is probably still here is because Charbit is hellbent on Demna's Balenciaga and his superiors are too busy fixing the mess at Gucci to care. Had Gucci Ancora been a success, it would've been a very different story for Balenciaga.
After Demna leaves, the brand will probably be forced to rebrand itself to appeal to the typical luxury demographic. Looking at Ancora, I see post-Demna Balenciaga becoming a very greige version of Ghesquiere's era, but with Olsen-esque flat hair and shoes.