there is only so far that magnetic technology can go and still be trusted.
to be perfectly honest here, i can see a point in time where we no longer have traditional mass size hard drives. im thinking it will happen around the time of holographic discs. a 200gb disc, bought for pennys on the gb (possibly disc), highly expandable, will be used for the long term, i dont need it now storage, and an ssd of 1-2tb will be used.
im looking at things in a realistic manner. there is a limit to how big a video can be before we cant distinguish detail anymore. i believe that for home purposes it will be a 4k standard, possibly a bit bigger. but for most people, the only way that you could see that detail is on a 100inch+ tv, and when was that last time you seen that for a commonly affordable price?
i have to say that at some point, like now, 12mp is all we need for photos, what most people want is better optics.
we dont need more than 1080p because we can barely see the extra detail because of how our eyes work, unless you blow the image way the hell up.
we hit close to the peak of what we need now, all thats left is refining it.