As long as she's alive, the shoes will not come off her feet. That's important for it means as long as the blood is being supported by the inner fire and vital energy, we still own it. It's only when the vital energy is gone that the life is drained from us, and this is usually due to injured instinct. Toto represents instinct, and he's not injured although the witch is making threats.
Dorothy doesn't give away her blood. She doesn't let the vampires suck it dry. She refuses to be a factory for the progeny of a sham sovereignty. Her own sovereignty is all that matters. She uses her ruby red slippers as the grounding vehilcle and foundation for her own ability to thrive and navigate the journey. And she requires no one's permission and no one's assistance. The Tin Man, Cowardly lion, and Scarecrow (and Toto too!) are all aspects of her being. They provide everything she needs to complete the journeyand go back home.