Interesting. PG provides a thought provoking opinion, and he's a fine writer. However, I think this idea is a bit naive. Sure, maybe he came to realize depressing, moody short stories weren't his thing, but I damn near guarantee his imitation of said stories was crucial to his learning how to write half-way decently. The vast majority of philosophers are not good writers. A few stand out as fine men of letters, Nietz…
I never understood this claim. I have to assume that people are letting their judgement of the content affect the judgement of the writing style. Plenty of canonical philosophers were absolutely beautiful writers - Plato, Hume, Nietzsche. Modern analytic philosophers are almost fanatical in their adherence to simple, straightforward language. The result might not be beautiful, but I certainly don't think you can call it "bad" either. Some philosophers may be bad writers (Hegel is a pain), but on the whole they seem to be mostly good writers. It's all that they do, after all.
>After all, giants are giant for a reason.
Well... are they? All of them? I think you can make this claim with a good deal of confidence about math and science, because we have a pretty strict set of rules for evaluating good and bad work. But do you really think that everyone in the artistic canon has a good reason to be there? What about all the still-living artists who have only recently been "canonized" via a flurry of academic attention (writers like DeLillo and Pynchon would be good examples). Are we confident that we'll still be talking about those guys 200 years from now? If not, how far back in time do we have to go before we can confidently say, "these giants have a reason to be giants?"
I'm not endorsing pure aesthetic relativism, nor am I saying that none of the canonical artists deserve to be there. I'm just saying that I've never heard a convincing explanation of why the canon is a good judge of, well, anything.