I understand where you are coming from in the topic. In a sense, I think you are making a point between the lines of lack of diversity and originality. There has been a repetitive nature to some role-playing concepts, then it could be some other idea that makes the original concept even better. Then, there could be the lack of patience of a person to keep it active and the idea simply dies or is revived.
So, with this happening over and over, people could become skeptical about joining groups. Making the assumption their role-play would not be interesting. Or vise versa, the role-play does have a great idea, but people are not all committed, outside activity happens, lack of free-time, etc.
My point is, if an idea is good and original, it would be great for someone to use it to its potential. Or, if they are not sure of the idea anymore, simply pass it on to another person who could modify it and continue share it with the community. Or, if that's not your thing, keep it to yourself, maybe the idea was too much for people to come to grips with. With an idea, alone, it all depends on the creator and what they wish to do with it.
As far as role-playing ideas falling, I don't think I want to go that far. While I do agree that there is that ounce of blandness, it takes other people to come and say, "Hey, would this be a cool idea?"
From there, do what you will, have fun, and if it doesn't work out, try again. *