I think there is a BIG reason why Haskell has not grown in popularity in language usage and is beat by Scheme and almost beat out by ML.

Is it? I would think there is easily WAY more Haskell currently in use in both industry and academia than Scheme. Certainly the mindshare is much, much larger. I have no idea where ML is, but it seems like it should be roughly on the same order as Haskell, and surely beating Scheme.