Not really, the reason isn't necessarily a lack of demand as it is an overabundance of supply. They are made available RANDOMLY when the Cartel Packs are purchased. Some people buy multiple packs and get more than they can use. So they sell them on the market. Everyone in the game could technically already want and get one (demand), and there would still be more on the market.
And of course it's my opinion, but the oversaturation of these items in the in-game market (GTN) seems to support a lack of demand. So there's that.