Every time some talented individual makes an adventure game with great art and concept, that’s a missed opportunity for cRPGs.
Adventure games require a tiny fraction of the content that RPGs do, and the design is totally different. It is pure happenstance if a good adventure game designer can design a good RPG.
Moreover, a good concept for an adventure game is not likely to be a good concept for an RPG. A concept that nicely supports a story about a solitary, mostly pacifist scavenger who goes around cobbling together improbable solutions is not likely to be a concept that nicely supports a story about a band of warriors who go around killing extraordinary numbers of foes while changing their gear every five minutes and growing exponentially more powerful. It's not just that the stories would be different; you need a concept that
supports those different stories. I cannot think of any adventure game off the top of my head that would fit well with an RPG, though perhaps a few RPGs (such as Planescape or V:TM:B) could support an adventure game.
There are obviously special cases like QFG or Lord of the Rings, but I still hold to the core premise.