Nano is a great example. It's superior to any of the currently existing coins in terms of speed and cost, but it can't gain momentum at all. If this was a tech company type of industry, Nano would take over, but not in crypto. 
And there's an easy explanation for this "phenomenon". Above all, the total majority of people involved in crypto are here for the quick buck and they don't particularly care for the technological innovation (I mean tweaks and Improvements beyond what plain vanilla Bitcoin offers). In simple terms, people may be interested in all these things only insofar as they add to hype and speculation. But if a coin is not used in real life (which is true to varying extents in respect to any cryptocurrency out there), its advantages like speed and cost are close to being completely inconsequential
This is the harsh truth how crypto goes, get used to it