Most people who are older fen haven't read Delany or Zelazny either. I didn't read Delany until last year and I was amazed at how relevant it was, how still-disturbing, how the only thing that felt dated was the use of subway tokens. But he is merely famous rather than actually being widely-read. Trouble on Triton has two orders of magnitude fewer ratings on Goodreads than Starship Troopers does.
Indeed, if Delany and Le Guin and Atwood were being promoted as The Canon, I think we'd see more people engaging with canon, because they do speak to current, pressing concerns.
(People might also read more of Heinlein if we had a functional public domain and things written 70 years ago were available for free on the internet, but oh well.)
I've read a lot of older stuff because my dad had a personal library. James Schmitz was the first things that spoke to me, because of course this 11 year old girl wanted to be a psychic with an invisible telepathic cat. But he's not part of canon either, because he wasn't Important Serious Works, and I wouldn't push him on others because his writings were frankly awkward and plopped cool, liberated women into sexist societies. Which may have reflected my experience at age 11, but doesn't mean anyone else needs to read it.
But I also don't expect everyone coming into fandom to be like me, maybe because not everyone in fandom has ever been like me. That's an experience I will never have that I think some white dudes in the 60's got to have and are still missing. Their experiences just aren't that important.