"It highlights a general problem with commercial art: do you make the art to appeal most to the diehard fans and make safer money? Or do you make riskier art in a new direction and hope it wins people over."

I agree.

Another thing is how studios/developers started their work. As others have mentioned here that "elf" went down by going another rather "darker" direction from their usual nukige romance formular. Although they were rather famous in japan people weren't fond of that and stopped consuming their stuff.

Its a bit of a double edged sword actually, I for myself wouldn't mind at least ONE good nakige from Yuzusoft instead of their usual feel good moege's but can they risk it? Or would they be willing to do so, if their current VN's are selling enough?

The problem with this in general is that there is not much leeway for them. No big publishers or sponsors who are backing them up, giving them creative freedom or even saving them.

One mistake could already be a death flag for them. Especially when it comes around with experimenting with the "purity" and faithfullness of the heroines from their usual moeges.