I'm honestly quite shocked that billionaire CEOs and all around shitheels haven't seen any assassination attempts. You see and hear constant criticism calling them evil monsters and yet not one mentally unhinged person has made them a target? I'm sure they have security and what not but the paparazzi have no problem getting pictures.
There was a Silicon Valley exec recently murdered by someone who also worked in the industry, which one may count as an "assassination", but this particular incident was personally motivated and not trying to send some sort of big message.