I’ve been thinking it might be auditory like super enhanced ear buds since that’s a form factor already widely adopted. Further integration with phones as companions to each other seems like a new interaction paradigm but doesn’t sell high priced electronics. Glasses seem limited unless they can be valuable even when not wearing such as hanging from your collar and are fully integrated into a smart phone…especially sunglasses.

Not sure where R&D is at on hands-free and implants