There's a lot of intelligent individuals especially hackers now a days. For me, I think bitcoin assures the security of their users so they come up of having paper wallet etc. So in our part maybe we should think a strongest password and make sure to always logout and dont share personal info:) to prevent this kind of event.
In theory, everything out there can be hacked. If you had sufficient computing power and sufficient time you could potentially break the keys for the bitcoin accounts by mere brute force. That might happen with quantum computing.