Rare goods have been sadly neglected by FD for some time.
I'm not sure that the profit is the main thing that needs fixing. Though it certainly wouldn't hurt.
What I think needs fixing with rare goods:
removing the piddling allocations for many rare goods
not having every state, except boom, reduce the allocations
alternative ways of getting rare goods: missions offering rare goods as rewards, purchasing from blackmarket
blocked rare goods should be sold on the blackmarket - opening one even if not normally present in the station (i.e. immune to powerplay and faction effects)
missions asking for rare goods (apparently these do exist, but I've never seen one)
news bulletins in rare goods systems, showing the status of the local rare goods
two rare goods still need to be moved, as they are blocked by player factions inserted by FD (Wolf Fesh and Gilya Signature Weapons)
Some rare goods should be able to be found in the wild, as it's in their descriptions. In particular: Soontil Relics, should be salvageable on planets in and near Soontil; Baltha'sine Vacuum Krill should be able to be mined in the rings of Baltha'Sine 4B