I think there's lots of development yet to be seen in the way of folding bikes.
Maintenance-free drivetrains will become the norm.
I also agree with a post above that we'll start to see a number of car-free housing developments in the near future.
And mountainbikes will one day be hoverbikes, with suspension travel and action set on the fly by adjusting the downward force of the hover technology. Possibly even be set by a forward terrain scanner that constantly reads and anticipates what you're about to hit and adapts the suspension to accomodate.
Ironically, depite the doubtless popularity these machines will enjoy, they'll have been rendered redundant as by this time any riding beyond the controlled confines of trail centres will be punishable by death, while the trail centres in question will have been 'managed' into consisting of nothing more than 8 foot wide ribbons of perfectly polished, mirror smooth trails circling pointlessly around forests filled with reactive foam trees and speed cameras, if in fact speed isn't remotely restricted by satellite tracking.