To be honest I would say up until this generation WRPG's were a bit niche and it wasn't until the genre released game more accessible to general audiences that anyone bought them in large numbers.

As for JRPG's, there has simply been a lack of innovation and quality and the genre needs to realize how they're going to evolve and adapt to survive in the West. Most Japanese RPG's that did well over here really WRPG's (Dark Souls, Dragon's Dogma). And with the exception of Xenoblade Chronicles, there's been a relative lack of innovation to keep audiences interested.