That's what Derpy's all about, it's why bubbles are her cutie mark. Elegant in their simplicity, a weightless lifeforce of purest innocence. It' mere existence a work of art, ultimately doomed to end in the most spectacular devastation. In an instant the serenity of such delicacy shatters to reveal the fragile nature that is . . . Derpy. [link] Just in case you're still not convinced.
As maaaaany have stated before, your artstyle is absolutely lovely! And on top of that, this piece right here is amazingly cute and masterfully done - i LOVE the detail you've put into the reflection on the bubble. It just makes me happy whenever I see this :3
Even if Derpy isn't in the show anymore, she's a fan character created by the fans, for the fans, and as long as she's in the comic in comedic situations and in fanart, she'l still be alive. Even if they remove her from the show entirely, our little Derpy-pony will still be alive!