The CX is used a lot. It’s just mainly used for beginner products.
The reason for this is game balance - there is no trading of higher tier products because nobody is making them because there is not much use for them in game. Basically, unless you are going to make ship components, there is no reason to move much beyond tier 2.
Let’s look at an example. WIN is one of the highest tier luxury consumables you can make, and DW is the most basic and easiest consumable. DW is kind of boring, you just purify H2O. To make WIN, you have to grow grapes, which require an orchard, and DDT chemicals, and then you ferment them with other ingredients. Sounds cool, right? I bet plenty of newly joining players look at the agriculture track and have a goal of making WIN one day.
Hold your grapes, son…
There are several million pioneers in the game, consuming 4 DW per 100, so that’s demand for at least 100,000 units of DW per day, not even including other worker types.
WIN is only used by scientists, at a rate of 1 WIN per 100. And there are barely 200 scientists in the whole universe, so that’s a total demand across all players of 2 units of WIN per day.
So, is it surprising that WIN is not heavily traded on the CX? No, it is not.
And this has nothing to do with vertical integration, corporation shadow markets, or the LM being over-powered. It’s that there is barely any demand for WIN in the first place.
The game balance of the tiers is such that everything is skewed towards the lower ones. If the devs want more production and trading at higher tiers, they need to change that balance. That is all.