I, for one, think that there will always be a market for guys with good taste. I think that there might be girls that are sick of effeminate "metros", but I don't think it is much of a "movement".
One defining factor of a supposed "metro" is that they are confident in themselves. I don't think you're going to see these same confident guys simply adopt an entirely new set of habits and style cues.
"Metrosexuality" (for lack of a better term, unfortunately), is not a fad. It is a label that has been placed on people who are living their lives in the way they see fit, which, amusingly, has nothing to do with sexuality and isn't meant to provoke any sort of specific response. "WE" don't want to be called that. I obviously say that, having been labeled one myself. I don't give a sh*t if girls appreciate the fact that I'm well-groomed. This isn't for them. This is simply ME, taking care of myself in the best way that I know how to and surrounding myself with things that I find interesting and attractive.
If there ARE guys (and I'm sure there are) who are going to go out and consciously revamp their image to accommodate any supposed impending movement away from "Metrosexuality", means to me that they probably weren't really "one" in the first place (I'm proud to belong to this group, but hate the label) and should probably try and find out who they are for their own self, not someone else and not to satisfy some stupid style trend.