Just read the OP , what he is saying is the truth. Your case study of yellow zone farming is not even close to valid in this conversation.
OFC the markets are great in the yellow zones because every casual player is sitting around in the saftey net. The black zone markets are dead because you have to travel like 15 clusters to each city.. no one is carrying mats/armor/weapons 15 clusters in full PVP zones JUST to sell it on the market.. they are simply hording all the resources for their gvg fights.. that's it.. not to mention guilds on the far east / west coast are NEVER going to fight each other.. PVP diversity is at an all time low... I dont know why im bothering responding to this.. but you just brought so much ignorance to this conversation that I felt compelled.
Black zone play is completely and utterly different from yellow zone play. With the current map layout, they should just re-introduce fast-travel between black zone cities the way it used to be, and go back to thinking "why did it go wrong with PvP in black zones?".
I bet that the real issue is almost purely a matter of perception - by isolating out black the way they did they made the barrier to entry higher. It's not technically higher though, walking through red and using a port is pretty much equivalent to old walking through red into black, but I'm guessing that alot of people that in the old world would've dipped their toes and gotten there, now chooses not to.
A couple of suggestion to solve/mitigate the issue (in no particular order):
1) Make zone sizes smaller as PvP rules increase in level (big green, medium yellow, small red, tiny black) and increase spawn rates accordingly.
2) Lock all zones after release and require that in order to unlock a zone (for everyone) an increasing number of people need to be present in the map for a reasonable duration (5-15 minutes). Number of people needed increases with number of maps already unlocked. All green zones should be unlocked by default. This will make the world stay small until the population is big enough to sustain value in the outlands.
3) Increase movementspeed on roads dramatically when no other player is nearby. (slow down when you meet someone).
4) Re-introduce fewer chokepoints to help PvP find it's way, for better or worse.
Now lets be clear here:
Fast travel removal helped green/yellow-zone markets, and those are thriving compared to before.
Fast travel removal hurt red/black-zone markets and competetive combat play - forcing people to refocus into what people aptly have described as the boring walking simulator.