Yes a writer should read “something else”. Because it broadens one’s perspective on how things can be written.
In my previous readings, I’ve come across thrillers, movie-book tie in adaptations, testimonies, essay and opinion, outrageous children’s fiction, and so on, but they are all written differently.
There are so many different ways of writing things that it prompts me to realize that the way an author writes something depends on the genre and the audience. This comes from reading various books–certain genres stick to a particular tone, reading level and ability, and a certain way of expressing something. An opinion piece for adults is written differently to kid’s fiction. The author’s general purpose may remain the same in whatever genre the author does, but one’s expression can change depending on the genre and the audience.
There is more to knowing genres than reading generic work, though. There are rules to genres that one can research before leaping off the deep end and writing generic work willy nilly, which is advisable to any sensible writer. But still, thoughtless writing happens, and I speak from personal experience as well as observation.
So, one can learn about the rules of genre of writing than break them if one wants to, as long as one knows what one is doing.
Learning the craft of a genre can be fun. Reading the genre isn’t enough, though. One must know the genre, which makes one understand the genre as one is reading it and writing it. I’ve been terrible at this, but if one is serious about writing in a genre, one must read it widely and learn it well.
And if submitting to a certain publisher one must study the guidelines and humbly read samples of other’s writing that have got published with that publisher. Sometimes, we must take a bit of humble pie and learn if we want to do writing properly and potentially get it published in places one is aiming at.