Hopefully terrorists WILL pursue this
If they waste their time with stuff like this, like Al Qaeda has wasted untold years trying to repeat their 'success' of 9/11 by continuing to target blowing up or making airplanes crash, that prevents them from doing things that are both more likely to be successful as well as harder to defend against.
Paris was a step forward down this road of realization for terrorists. Instead of trying to attack well defended targets, they chose more random locations like a rock concert. While we may be able to step up security at major locations like say Heathrow, the Louvre, the Statue of Liberty, etc. we can't possibly maintain that level of security in every location where people will gather - or even throughout more obvious targets like airports.
For instance, I've long thought terrorists would be more successful in attacking airports if instead of trying to get bombs through security, they simply get themselves into a big long line caused by that security and blow themselves up while surrounded by dozens or hundreds of people waiting in line. How could we respond to that? We can't, because no matter what perimeter we set up, it will cause a line waiting to pass through it, where a suicide vest or car bomb will be effective at killing bystanders waiting in that line!
The example from the article of walking down the street and shooting people is a good one. Previously people might have only felt exposed to terror in certain locations like the airport, but if they had a few episodes like this they'd be worried about walking down the street. If instead of attacking major cities like London, Paris and NYC they took their "walk by shootings" to random smaller cities like Oxford, Lyon and Jersey City, people would feel vulnerable everywhere, not just if they lived in or visited a major city.
At that point we'd either have to be fearful and hide in our homes all the time while living under a police state that did little to actually protect us, or decide that it really doesn't matter because the odds of dropping dead on the street from a heart attack or in a car crash on the way across town are and would remain much higher than the odds of dying at the hands of a terrorist, and we shouldn't worry about it so much. The attitude of the people of Israel being a good example there.