Jita is the main trade hub in all of New Eden. The game has something like 50 regions but only one major trade hub. Why is this?
The first reason is that its too easy to get to Jita. Economics are ruined by the same thing as nullsec, power projection.
The second reason is goods. There are not enough major goods to support multiple hubs. In the real world we have tons of goods that need to be supplied locally and often produced locally.
The third reason is population. EVE just doesn't have enough players for non-empire systems to need their own hubs, and anyone in Empire can too easily reach Jita.
The last reason is size. The EVE universe could really do with about 4x its current size.
The easiest way to make changes is a system suggested previously by PCC members. Break up the kiddie pool. If we split empire by a river of null and low space this will at least force hisec players to create 4 hubs, one for each empire. This will also provide many other fun and interesting effects and opportunities.
The more difficult way is make New Eden, primarily EVE, 4x bigger. This will resolve a number of other issues EVE has as well.
Other options may be more obnoxious. One would involve a little less "fun per hour" perhaps but would be good for the overall health of the game. Players should ideally require some high volume, cheap, locally producible goods to consume every day in order to survive. Perhaps increase training time if consumption is not kept up. This would require players to seed a market which could then provide the seed for a larger market to grow in each region.
Regardless of the limited downsides to various ideas, they would provide a much more robust market potential for a game supposedly all about market pvp.