Walburga definitely outlived Druella, Cygnus and Orion purely out of spite and probably died soon after Sirius went into Azkaban, drifting away happily knowing her biggest failure didn’t turn out to be a failure at all.
Imagine the portrait welcoming Sirius back like a king the first time he walks through the doors. She is so proud her son went to Azkaban to help the Dark Lord and then the rest of the Order comes in and Walburga finds out the truth and all hell breaks loose. They grab the closest piece of cloth they can find and Remus charms it so it shuts the fuck up and thus Walburga’s fairytale comes to an abrupt end.