There'll always be a market for hardcore or traditional game types, but developing them requires a larger investment of time and effort, and therefore I suspect that most independent developers consider them to be too risky to take on.
Adventure games lend themselves well to mouse control but developing an adventure game is a huge undertaking, requiring high-level skills in a multitude of artistic areas (art, music, writing). And they represent a subset of a relatively unpopular niche genre which only makes things worse.
Adventure games lend themselves well to mouse control but developing an adventure game is a huge undertaking, requiring high-level skills in a multitude of artistic areas (art, music, writing). And they represent a subset of a relatively unpopular niche genre which only makes things worse.