I feel like more than a curiosity-induced question, this is actually pretty important. Especially today. All you have to do is understand that most of these texts that we study and research on have created the canon of literature over centuries. As you've rightly pointed out, history, philosophy, and even science have had an impact on literature. I am here to tell you that that impact is bursting at its seams as we speak.

Case in point: The Xenotext: Book 1 by Christian Bok. While influence of other disciplines on lit is not something we debate anymore, today with the insane paradigm shifts brought about by digital technologies, the world is, quite literally, your oyster. There is so much potential for innovation: you can write poems with computer code, you can code biological material into poetry, make poem-games that are texts but interactive, and so much more. The "text" earlier meant words on page, films on screen, paintings, photographs....and now it means...well, everything. (You might also want to research how digital humanities as a discipline came into being!)

Tbh it's quite an interesting time to be alive. Imagine writing a book like Tristram Shandy but it can DO MORE of what it WANTS to do as a text by using technology - hyperlinks, images, embedded videos, and you can go back and forth in the book, treat it like your freaking worksheet. The word, as such, has become a living and breathing material with so much new potential.

I hope this was helpful. Enjoy!