I have seen several knives fail to various degrees, generally because of misuse or using beyond its design capabilities i.e. throwing, battoning, cutting improper material, or some other task the knife was not designed for.

Any knife broken at the hilt I know of as Rainy Day's knife was, was due to lateral force put on the blade when it was stuck in something like a tree or used a pry bar. I knew a guy that put a 50's vintage stag 1-8 in the sheath on his table that looked great sitting in his case. Many would ask to see it and when they took it out of the sheath, all you had was handle and hilt. Broken prying open a crate.