How can OP think that a virtual currency which don't need banks for transaction will be disappeared ..
Bitcoin can't be hacked it can't be stolen easily then why he thinks it's possible ?
Maybe because OP thinks that bitcoin has a really great potential which is enough to make a revolution. A revolution that would make people switch from using fiat/bank into using bitcoins. Once people realize the advantages of using bitcoin, they might forget using banks. Banks are just businesses that needs users in order to continue running. Once people are not using banks anymore, it will eventually shut down. I guess that's the reason why OP asked this, he wants to see how realistic this idea actually is.