At some point there will be a push in the more crowded areas to go narrow to open up more repeater pairs. A problem which could be solved in many areas if the coordinators would do their jobs and de-coordinate non-existent repeaters.
Not to prolong the agony (I'm going to do it anyway!
) but I don't think you'll see that. The two meter repeater frequencies have been full in many areas for many years now, and there isn't--with a few exceptions--any sort of move to change to narrowbanding. It's simply seen as not necessary. Add to that the amount of equipment that would have to be replaced and/or junked by ham operators, and you'll see that any sort of a move to do that on a national scale would come up against some strong opposition. It has been done in some small areas, but I don't think you'll see it being widely done for quite some time--if ever.