Teal Deer: It depends.
At length: I am on record stating that there should be no barriers to entry when it comes to fandom, and I stand by that position. Consequently, I refuse to impose arbitrary reading lists on other fans – even if said lists cover older authors I personally admire.
However – if you aspire to write science fiction or comment upon its history, then I damn well think you should read Heinlein, Asimov, Clarke, and other major authors of the genre, as this sort of survey will help you to avoid irritating your potential readership with false marketing and/or broken promises. Further, it certainly wouldn’t hurt to become acquainted with what these authors actually believed with respect to political and social issues – not to mention how those beliefs compared to those of their contemporaries.
It chafes me to no end, for example, when current-day science fiction commentators proclaim – as they so frequently do – that the exploration of heterodox sexualities is “exciting and groundbreaking.” Wait: When was The Moon Is a Harsh Mistress published again? Wasn’t Heinlein writing about plural marriages in the 19-freakin’-60’s? No: Science fictional challenges to the Judeo-Christian sexual ethic are at least fifty years old – if not older. If you fail to read the classics, you will lose that critical perspective.
Equally as irksome: Charges of racism/sexism/homophobia that ignore context. It’s easy for us to declare early science fiction works “problematic,” but authors in the 1960’s couldn’t possibly have known how social mores would change. Expecting said authors to line up to your exacting post-modern standards is presentism – and it’s deeply unjust.
Reading the classics will also help complicate the popular narrative regarding women and their history in the genre. Among the young and unschooled, it is often held as axiomatic that female science fiction writers did not and could not succeed either financially or critically until very recently. This is false. Women have been influencing the field as writers, editors, and award winners for decades. They don’t need any special favors.
And if you are an author? Reading the classics will acquaint you with the genre’s norms. You have to read the Big Conversations before you add your two cents. You have to learn the rules before you seek to stretch or break them. Attempting to write science fiction without striving to be minimally familiar with the fundamentals is like trying to write a persuasive essay without learning how to write a grammatically correct sentence. It doesn’t work, and it leads to pseudo-science-fictional tripe.
And for what it’s worth, while I will not demand that every casual fan read the Big Three and the rest, I will continue to recommend that people do so. Is the crisis of faith suffered by the protagonist of “The Star” really inaccessible to today’s reader? Will our kids really fail to connect to Charlie Gordon’s longing to belong? Dated though some of the details may be, the best stories have still held up. We shouldn’t let contemporary – and misguided – demands for “relevance” consign these works to the dust bin.