There is also a future problem. Quantum computers could crack bitcoin. The block chain itself to rearrange the history of transactions to change balances or just attack individual wallets which would be easier, obviously, the ones attacked would have the largest amount of bitcoin.

This is about 10 years off, but possibly sooner with the individual wallet attacks.

Of course this is a problem with all cryptography and new codes are being developed to be more quantum resistant. Bitcoin as it is is doomed though.