Think about how you didn't really hear about movie theater shootings until someone shot up the one in Aurora. Now they're more common. There is a huge element of social contagion because shooters are very much copying each other's work.
Which would suggest that we would see a rise in CEO assassinations over time[0]. But the thing is, it's also legitimately harder to assassinate a CEO than shoot up a school. Schools are soft targets with predictable schedules for their occupancy. A CEO might be in 20 different countries over the course of a month; you'd have to engage in a LOT of cyberstalking to even have a chance of catching a CEO in your hometown. And not to mention, they usually have security detail specifically to prevent this exact thing from happening.
But who knows. There's a lot of people pissed off about corporate power, in every country, across party lines. It only takes one security fuck-up.
[0] This is what the phrase "propaganda of the deed" refers to
He moved the needle, people are talking about it, maybe thinking about it a bit more.