What does the soles of both sneakers were hanging by their hinges and flopping open like a dog's tongue mean?

The phrase suggests that the sneakers are in very poor condition, with their soles almost completely detached and dangling loosely. The comparison to a dog's tongue emphasizes the floppy, helpless state of the sneakers, evoking a vivid image of neglect and wear. This imagery conveys a sense of abandonment or disrepair, highlighting the sneakers' unusable state.