If you think they are about questions relevant centuries ago, I'd really like to know what you think the questions are.
Many of the "classics" of classic literature (no pun intended) talk about questions that are perpetually relevant, and the same goes for lots of things that fall under history and philosophy.
I don't debate there's a lot of garbage out there that falls under "it's old, so we'll teach it", but I can assure you that the vast majority does speak about relevant topics. And like in SF, the ones that endure are the ones that speak most clearly.
In general, all stories teach about empathy - how can I put myself in somebody else's shoes. If you found a better way to learn that via SF, more power to you. The classics are still relevant because they provide the foundation upon all this is built, and so they become important once you discuss things in a wider circle. (E.g. I might like fantasy, and not have a solid enough grounding in SF. We need to find some common ground. Via acclamation, the world has picked literature/history/philosophy as that common ground)
And so I'd encourage you to maybe go out and give some of it a try :)
If you care for recommendations: For philosophy, I recommend "What does it all mean" by Thomas Nagel. I don't have a great recommendation for History - I like "By Steppe, Desert and Ocean", but it's incomplete & somewhat eurocentric. True world history in a single book is probably asking a bit much. Same goes for literature, but even more so - it's really a matter of taste. I adore "The Master and Margarita", but beware, it's weird :) Grapes of Wrath is a moving and v. relevant one. The Illiad is spectacular, but I only know German translations, never read it in English.