It's looking like the stat bonuses from materia are roughly comparable to the stat bonus gained from a +3 item (perhaps slightly smaller, but more flexible).

As an example, my weapon of choice, an [item=4080301]Iron Halberd[/item] +3. Base stats on Iron Halberd are 169 attack, 150 accuracy, critical 142. So, the +3 adds 26 attack, 23 accuracy, and 22 critical. That is, I could get the same effect by using an HQ Iron Halberd and socketing in three materia with these stats.

So, if an HQ item is roughly equivalent to an NQ items with 3 or 4 materia (but the NQ item is more flexible as to what the bonuses are), this progression makes a bit more sense.

Additionally, the possibly loss of the HQ item is a necessary part of the adjusted economy, as it is the only realistic HQ item sink in the game. If HQ items were not lost, then saturation would occur once each player had bought a single HQ item of each type.

With the proposed system, a player will start with HQ item with 1 materia. This will likely be stronger then an NQ item with 5 (or roughly equivalent). However, the player still has a need for another HQ item, if the price is suitable. Slotting a 2nd materia into an HQ item, while owning just the 1, is too high a risk. However, if a 2nd HQ item is bought at a satisfactory price, then the risk is substantially reduced.

This system will essentially stabilize HQ item prices over a long enough period of time that the dev team had enough time to introduce new gear before the market reaches saturation.