Robert Ewing said:
In a nutshell, all the ideas are gone. They've done basic Western medieval fantasy, western sci-fi fantasy, eastern medieval fantasy, eastern sci-fi fantasy. All of the other scenes that an RPG inhabits. Where do you take it from there? It's widely believed that all the ideas combined to make all these separate genre's have been used. It's not easy for a games company to reuse those ideas and make them better. Because 1, they can't copy ideas. And two, they often turn out to be worse.
You don't always need a new setting, you know. You can still make an original and memorable high fantasy RPG (for example). Just make it your own type of high fantasy world.
Look at Radiant Historia: It's high fantasy alright. Magic, Mana flow, some guns and steampunk, but still mostly swords spells and kingdoms. But it still feels fresh and original.
Plus, there is a setting we have not explored much: The Modern day "urban" RPG. You know, Like Earthbound, and TWEWY? I'm surprised we haven't seen more of those.
There is still plenty of originality to be found. We've just become conditioned to shrug off the more typical stuff like "Join rebels, overthrow evil empire" and "chosen one who must save world from impending Lovecraftian horror by gathering 3 magic muffins".