Apple has filed patents that would allow a device's screen to respond to the user while immersed in water and that allow for rotation that adapts to a human face's orientation. These documents' images suggest that they are intended for mobile devices. Therefore, next-gen iPhones could come with these features.
https://www.notebookcheck.net/The-iPhone-of-the-future-may-work-underwater-and-have-advanced-auto-rotation.459872.0.html
The idea of making iPhones more usable underwater is really interesting, especially if Apple can improve touchscreen input and water detection. Until phones get features like this, though, accidental water exposure can still leave speakers sounding muffled even after the phone is removed from the water. For minor moisture in the speaker grille, I've found ejectwater.com useful for playing a water-ejecting sound directly from the browser.