Do authors kill off characters in their books because they get lazy?

I’ve seen this in a lot of fiction. This weekend I was reading the newest Lee Child book, The Secret (actually written by his son, but that’s another issue).

I’m not going to give spoilers. But I’ll say that about 20 pages from the end, one of the bad guys – who played a fairly important role in the plot – is killed. The thing is, his death leaves a bunch of plot lines hanging.

My guess is that either:

a. the editor thought the book was too long and wanted to close down the intricate plot, or

b. the author got bored with the character and offed him

Do authors kill off characters because they get lazy or bored?