The way I see it though, the limitations of CI implants are primarily driven by the internal electrode interface that limits the number of available frequencies to the person. This isn't something that any of the "big tech" companies are positioned to innovate in. I'd be more interested if Hewlett Packard got involved because they actually have a significant and successful micro/nanotech group.

Hearing aids though could be ripe for disruption by improved computational power and large supply chain leverage. So it will be a matter of whether or not Apple/Google/ back off once they meet the intractable reality of regulatory compliance in a limited market a la their infrastructure plans.

I think it's most likely that they will buy up those medical companies for expertise, then spin off the medical device manufacturing into a new separate company or otherwise sell it off but keep the key engineers to roll into other random consumer products that are less regulated and more profitable. This is what Google has more or less done with robotics after buying basically every major robotics research company in the US a few years back.