Haven't read ACOTAR, but isn't that YA stuff? If so, I think it's pretty common for that kind of genre.

There's a ton of more adult fantasy, where main characters do die. The most infamous is probably ASoIaF. Malazan and First Law come to mind as well. Or try Nevernight, which fulfills many YA tropes (teenage girl joins a school for assassins) but is definitely for an adult audience.