I honestly tend to think its the result of unprecedented safety. We are hard wired to be on the look out for danger, when there is no danger and we will find it if we look for it. As you make real danger more and more rare, sensitivity goes up.
People being murdered every day can be a fact of life, people murdered every few days is a tragic situation, a person murdered every decade is a major news event.
Also we have an issue of expanding scope. Lets take car accidents, mundane ones are local stories, odd ones are regional, and that strange few times a year spectaculars are national.
If you decrease the numbers, all that changes is scope, you still get as many stories, they just come from wider areas.....so the input never really changes even if the output does.
These airplane incidents are international news and run for days and weeks as such.... which makes them seem a lot more common than they really are because they take up such a disproportionate amount of the news when they do....because news isn't meant to be boring and mundane, it is, by definition, the unusual and the rare.