Not necessarily. Many people pay for 2 TB without actually needing 2 TB. I currently pay for Dropbox Pro, which has 2 TB of space available, but I'm only using 300 GB. I'm pretty sure that at this point people going over 500 GB are a tiny minority.

When you pay for 30 TB on the other hand, you probably need it, so their actual cost might be reflected well in that price. This is basically the long tail effect, so when you optimize the price for the majority, price increases are not linear.