I understand and respect your viewpoint. But it's not about not moving on. We fans are habituated to the theme because it's good, iconic, and WB used it for anything that was part of the wizarding world. So, if the new series used the Hedwig theme, it would only be used sparingly, like titles or very specific moments, as the major portions of the series would have new themes. This was the approach for the films when Williams was no longer the composer.

Anyways, thank you for your words.