Most hacked bitcoiner cause of using malware/phishing wallet/software/website, some of them while using electrum and got phished by installing from malicious server the prompts as a notification. While some of them while using exchanges that were hacked.
The lesson is always verify the source/signature of every wallet you want to install on your device. And don't ever put your bitcoin on exchanges for a very long time or as an alternative for wallet.
Pretty much is a victim due to this kind of attack but there is a small percentage that are caught not because they are going into this sites but they are a big mouth and they are arrogant which means that they blabber about how they are hodling bitcoin and how he/she will be rich and such which could be a good thing for attackers because they can just listen to this arrogant people brag about their bitcoin and the fine details without the effort of going for a full technical route.