It's simple really. Dogecoin can fail because demand can't keep up with 10k coin block reward every minute for eternity. People don't understand that demand always has to increase at least by the amount that total supply goes up by, otherwise the price will fall. Inevitably there is no way price can go up due to this. Just simple economics.
Price-wise, Dogecoin will fail. But I think the network will survive thanks to the way it was designed. There's a respectable number of nodes and miners backing the DOGE chain, so don't count on its disappearance anytime soon. The creators of Dogecoin always said it was never meant to be used as a serious cryptocurrency. With the huge supply alone, DOGE will be unable to maintain a high price for long.
At least, the network is fully functional. Who knows if DOGE gets to outlive most coins in the future? Just my thoughts
