From the author: "Those who ignore history are doomed to repeat it". Those who ignore their Science Fiction history are missing some great stuff. If you're a writer, you may be doomed to recreate it. Poorly.
Often in my critiquing group, the discussion turns to a classic work in the genre or out and the group will be divided into those who've read the subject work, those who haven’t and those who’ve never heard of it. The latter two usually ask, "Why should I read it?" There are reasons for and against and all valid to some respect. Though I fall mainly on the 'why' side, I'll examine the 'why not' and the 'don't bother' position.
Let's examine the why first. You never suffer by reading an outstanding story or novel. As a writer, you can read jointly for enjoyment and to study technique of someone who pulled magic from the muse to create a classic. There's another reason besides entertainment or craft building. Most 'How-To' genre writing books emphasize early on that one should 'know what has gone before'. Science Fiction has a rich century-plus legacy. A burgeoning author can attempt a story about a Martian invasion failing due to earth virus/bacterial infection (or an alternate history Mayan invasion of medieval Europe defeated by smallpox) but know the ground has been well-tilled by H.G. Wells. This is an extreme example but many such classics exist without a series of movie adaptations. One could craft a story about a desert planet civilization breeding the finest warriors in the galaxy but don't try to market a Dune clone out of ignorance of its existence. A chance exists your first-reader group may not have read it either but a competent editor (and well-read fans) will have. Your work will be compared to precedents as well as contemporaries. If found to be a weak imitation of a landmark story of years ago, it may not pass the slush pile.
One of the reasons I hear for not reading this or that particular seminal work is a frustration in style evolution or biases no longer politically correct. But such differences can often inspire a new take. Consider Don Sakers' 'The Cold Solution', a more culturally acceptable answer to Tom Godwin's classic 'The Cold Equations'. Sakers created a classic of his own while paying homage to a decades-old but perceived out-of-date standard of the genre.
Knowing the history of the genre one is writing in can be essential not to unknowingly imitate a common theme or idea and can stimulate an entirely fresh approach. What if the classic's assumptions are wrong? What advances in technology or human understanding render the original obsolete? Respond with a modern interpretation.
Writers must be judicious in their time budgeting. The question arises of 'Why should I devote precious writing time to reading time?' A valid point, if the two are interchangeable. Twenty minutes on a bus ride or in a doctor's office could be more rewarding as a reading session than a writing one. Often for me, reading recharges the muse, plants ideas in the conscious or subconscious for future exploitation during the creativity process.
A more gut response to not pursuing the classics is sometimes just being contradictory for its own sake. Writers are a quirky bunch and expecting them all to react or behave as I do isn't realistic. I recognize the diverse personalities and respect their unique approaches to the creative process. The diversity is welcome when it comes to critiquing, if you please everyone, you're not doing it right.
The response is the 'I'm unfamiliar with that story'. Again, a valid position but not for the growing writer. Occasionally we have mystery and horror stories tabled for critiquing by our group. I've heard the 'I've written a cozy mystery but have never read one so I don't know what they are or if this qualifies' introduction. I leave it to the reader to react without editorial comment from me.
I remain on the 'for' side. I like being entertained and stimulated by reading the best, and this extends beyond the classics to the yearly Best collections to see what's being explored recently. I can appreciate the idea some writers don't want to be influenced by another author's take on a familiar theme. But most SF themes are familiar, it's the fresh execution which elevates your story out of the slushpile.