100 Billion coins for the masses is really not that many.  

The reason there wont be many Doge Billionaires is because people will trade it way before it ever matures to that level. Generally the nature of greed and fear will do this alone. And hopefully people will use their wealth and not hoard billions of coins.  

If a few people hold most of coins without using them then we won't see it's full potential.  It's takes the proper use of money to make money.  

But the future holds many great possibilities.