4TB seems like the upper end for most normal consumers, I would hazard. We had 1-2TB HDDs a decade ago, and there's been little reason to go higher in the consumer space. Arguably SSDs only now getting cheap enough at those capacities might have limited it, but even so I think we're running out of things that consume that much space.
Video and pictures are the main culprit (even in games), but 4k is likely to be the upper end of consumer usage for the forseeable future, photos have been 20-40MP for a decade, and perceivable quality benefits from going higher are fairly minimal. We can always use more space, but from a practical perspective there's not the same explosion in space required from everything else scaling to use it, I'd say.
I think videogames are the most bandwidth-hungry workload that most normal people have, so I think it would be hard to justify this sort of drive otherwise.
Video and pictures are the main culprit (even in games), but 4k is likely to be the upper end of consumer usage for the forseeable future, photos have been 20-40MP for a decade, and perceivable quality benefits from going higher are fairly minimal. We can always use more space, but from a practical perspective there's not the same explosion in space required from everything else scaling to use it, I'd say.