Non-technical factors could still matter enough to change what technology the market decides on.  AFAIK, nobody is really making a huge profit on bitcoin itself at the moment.  If it were to become profitable for a powerful group to run a different system, I think they could do it.  Maybe if for whatever reason Titcoin worked better for the porn industry (a group that definitely sees the value in anonymous money transfer via Internet) and couple big porn sites started promoting and accepting Titcoin, they could get enough advertising together to make Titcoin seem more attractive to the typical end-user.  Or maybe Bob Zitman The Big Businessman decides to invest heavily in an e-currency exchange site, and drops a few million dollars on a PR campaign for Zitcoin (because he thinks he can make a lot more than a few million if enough people use his currency.)