I think i never heard any news regarding an account being hacked, so the security of bitcoin wallet is still solid, the one that being hacked usually it's from phising site and suspicious link
And hopefully it will never being able to be hacked so we don't have to worry about our account
I didnt hear some new too related to online wallets that is being bruteforced to hack and stole of the bitcoin inside it but the incidents of being robbed because of virus and phishing link then i would really believe because if someone would able to know the important informations regarding on your wallet then the risk of being robbed is high.