That raises a good point. Maybe you can create bank vaults to store our inventory and wait for the rarity to increase.
Also, we do need much better ship offerings based on the time or date of the game. If I am playing 10-15 rounds, my cargo is probably 1000 or more and have decent weapons. Ships being offered should certainly compete with this and maybe offer certain benefits that I simply can never buy. Please consider this.
It's noted in the patch readme: U is for Uncommon. It has a slightly different price scale than Common does, and doesn't come up as often for sale as Common items.