If everyone in a country switched over to cryptocurrency, how would those with a lot of money keep their money safe? In a bank or...?

Say in the future traditional banks have all closed down because of cryptocurrency and thieves know this. Would't thieves start targeting people's phones and computers for bitcoin?Like if a bandit pointed a gun at someone right now who only had cash or debt card, they could just hand the small amount of carrying cash or card over and they could even call the card in later. But if the bandit was after bitcoin and had a phone with them and said: "give me all your bitcoin now, transfer it into my phone, or else", then they could potentially get away, anonymously, with all said persons bitcoin.How would people secure their money?And they don't want to put their phone or computer in a safe. via /r/Bitcoin http://bit.ly/2emUCIC