Probs they expect a 2TiB plan user to never use a significant amount of the 2TiB. Whereas the 10TiB plan user is more likely to use a higher percentage of allotted storage.
I agree. The price/GiB between looks like someone was throwing darts.
I wish there is a straightforward pay-as-you go option. However there is the mental downside that everything you store is costing money, whereas the package deals you feel free (until you hit the limit).