I believe it comes down to perception of the product. You already have access to that area/zone. Why would I purchase an expansion that only reskins the zones? Why don't they just add it as a free content update? Ect ect. Its a much harder sell to have a expac that takes previous zones and changes them. Not to mention the possible outrage that people can have towards their favorite town being changed. Look at freeport in EQ, and a large chunk of WoWs expac: cataclysm. Some people quit those respective games due to this, albeit a small handful. To a niche/indy game that is a much larger %.Why they can't just add the more useful content to the existing content and shred the fluff is beyond me.
I don't think we'll have a true solution until good content is able to be made via AI. Deepdream and Deep neural networks are on the right path for this. The biggest cost for content creation is visual, usually coding the mechanics of a fight, or writing the story takes a fraction of the time. Once we are able to put in story, style, and theme into a program and have it spit out results in hours/days vs months, you'll solve almost all the complaints I've seen from the crowd on this forum and others. The companies are businesses, and at the end of the day they have a cost/benefit ratio they have to adhere to. 18 races with their own starting towns, areas, story, ect is not in anyway a good cost to benefit. Maybe if a rich eccentric decides to make their own company in Rhode island that doesn't care about the bottom line and just wants to make a stellar product that everyone will love...