I can do one better: I can mention a hugely popular and commercially successful writer -- whom you know of, at least by name-- who used to live from paycheck to paycheck, really struggling when he started (before succeeding enormously, of course) and who wrote in the introduction to one of his books:
"Painting. Sculpture. Composing. Singing. Acting. The playing of a musical instrument. Writing. Enough books have been written on these seven subjects alone to sink a fleet of luxury liners. And the only thing we seem to be able to agree upon about them is this: that those who practise these arts honestly would continue to practise them even if they were not paid for their efforts; even if their efforts were criticized or even reviled; even on pain of imprisonment or death."
He struck gold, of course, but note the sentiment he expressed. By his own admission, had he never been paid for it, he would have kept writing anyway, because that's what he does. And when he was starting he had other jobs -- and a family to support -- and really struggled with money, but kept going anyway.
All the greatest writers, painters, composers, sculptors etc. dedicated themselves full time to their art. You just can't reach a comparable level of mastery by dabbling in your spare time.
First, this is a secondary discussion. Mastery? That wasn't the argument. The argument was about whether writing books can exist separate from monetary compensation.
Second, as has been mentioned to you in another comment, mastery is not directly related to having been paid for your art. There are acknowledged poets whose work was published posthumously. They didn't live off it.
(The quote was by Stephen King, by the way. Regardless of what you think about his literary skill, the man sure can speak about writing).
I never said I didn't care about quality, just that the discussion you entered was about whether books would exist without payment and whether only the "insane" would still write. You seem to want to take the argument on a tangent, but please read again the post which sparked this thread. What the original comment asserted was patently false.
"Painting. Sculpture. Composing. Singing. Acting. The playing of a musical instrument. Writing. Enough books have been written on these seven subjects alone to sink a fleet of luxury liners. And the only thing we seem to be able to agree upon about them is this: that those who practise these arts honestly would continue to practise them even if they were not paid for their efforts; even if their efforts were criticized or even reviled; even on pain of imprisonment or death."
He struck gold, of course, but note the sentiment he expressed. By his own admission, had he never been paid for it, he would have kept writing anyway, because that's what he does. And when he was starting he had other jobs -- and a family to support -- and really struggled with money, but kept going anyway.