In general, more flexible and multi-dimensional data structures demand higher abstraction and complexity of storage systems unless lower performance is acceptable. In some cases, lower performance is more acceptable than higher complexity, especially when the data to be processed are comparably small and should be changeable by text editors.
Another important factor in storages is performance-cost balancing. The larger, faster, more reliable a storage becomes, the more it costs. When this rule is not applicable to some costly products, they are to become cheaper or soon disappear from the market.