As it stands, DarkCoin can live forever, if the artificial 84million cap were removed. It is still rare, it takes a century to get to 100 million. Look at the United States Deficit! It's in the Trillions! And people think 100 million coins for the world population is too much?
Bitcoin won't die just because it'll stop producing coins at some point - otherwise no-one would buy it thinking it's dead and buried already. There's still transaction fees to be mined after the coin generation phase and if the coin has endured for so long, that means it will have transactions.
Finite and scarce coins are always better than infinite crapcoins. The elite-hoarding argument is true for every single coin in circulation. If the elite have the money and want to buy in, they can buy anything they like and hoard it.
It is not infinite if the demand outpaces the supply, by a lot! And bitcoin is already stagnant. It sits like gold in a vault, under your bed, behind the couch.
Let's say you have bitcoin which has 21mn coins but it will be destined to grow for ever and it's a bad store of value. Thus its price is low but it's highly liquid and nobody hoards it. Thus the price is, say, 10$ instead of 1000$. This means that there are 21mn X 10$ = 210mn USD in bitcoins that can be moved around for commerce / payments etc.
Now, let's change that and make it finite. 90% of people hoard bitcoin and the price goes from 10 to 1000$. Thus ~19mn coins are in hoarding and ~2mn coins are in circulation for commerce. However these 2mn coins can now handle commerce/payments/trade etc of 2mn coins X 1000 USD each = 2bn USD. You would actually only need 200.000 coins of 1000 USD each to cover what previously required 21.000.000 coins at a price of 10$.
You see the spike in price for the hoarded coins allows for a much lesser number of coins to cover commerce / payments / trade or financial daytrading. So it's not really a problem. And now the coin not only serves for trading/commerce etc but also as a store of value as well. You can't go wrong with this.