Dogecoin = infinite
Bitcoin = scarce
Dogecoin = abundant
Finite / scarce = better price than infinite / abundant. It's just the way it goes with supply and demand. Basic economics.
Scarcity is a good reason to drive price up only when the item has tangible value. When the value is purely speculative, scarcity (and deflation) will kill the trading and it leads to poor market depth and frequent price crashes.
Bitcoin will be dead when it gets fully mined. Doge will keep on marching towards the moon.
This is why few people say iCoin might be the main coin in a year as it has 900 year mining cycle.