“Because it was started earlier and has had a greater opportunity to grow and attract users, Bitcoin has a market larger by a wide margin than all the markets of all the altcoins put together, and this makes it vastly more useful as a currency. To defeat Bitcoin, an altcoin would require not just superior technology, but such vastly superior technology as to be an advance over Bitcoin comparable to the advance Bitcoin represents over fiat currency.”
http://themisescircle.org/blog/2013/08/22/the-problem-with-altcoins/
