I think the pricing is what it is partly because their main cost is not actually the storage space, but data transfer and computing. However to keep things simp

I think the pricing is what it is partly because their main cost is not actually the storage space, but data transfer and computing. However to keep things simple and predictable for the customer, Dropbox is not directly charging for these. Just think about the traffic you can easily generate when you have some work projects sitting on Dropbox folder. All the builds, downloading libraries, getting node modules etc, people working on large documents etc. The cost to provide 100GB of space vs 1TB of space might be actually pretty close for Dropbox (considering also that very few people actually use all that space). Other providers may have different cost structures. Maybe the services they are providing are bit different (for example less focus on sync speed), or maybe the customers are using the storage in very different way (I guess most of the content in iCloud is photos and videos).