[01100011]

I agree but to play Devil's advocate I think the answer is "the network effect". Facebook could be replaced at any time, yet it continues to dominate social media. At some point, BTC could become, if it has not already, big enough to become self-sustaining.

[rdsubhas]

Regarding free services, one could have said the same thing about Orkut or Myspace. Community tends to flock in via one door, and flock out via another door, as long as the product or service is free.

In this case however, completely agree with you. BTC is a paid network (a very expensive one at that). It could remain self-sustaining for quite long.