The reality is a little different. He'll spend a certain number of hours each day writing new material for next years book, some time researching the book he's thinking of writing the year after that, a couple of hours editing the book that he's planning on releasing later this year, an hour reading (again) the galleys for the book his publisher wants final approval on. After which he'll be updating social networking sites, blogs, accounts and other business tasks related to his job.
There are abundant similarities to the indie developer - and maybe a little hope, too. If we need a break from the coding, there's always art needing to be done, or music, or sound effects, or web design, or marketing. Maybe we're doing it ourselves (and does 'programmer art' really need to be a pejorative?), or maybe we're incorporating art and services created by a third party, but either way we're forced to switch tracks regularly.
I take a measure of reassurance from the author's approach. Like the author, we find ourselves switching mental tasks - we are analytical, then creative, then critical, then business, then social... To an outsider I suspect it looks like we're suffering a multiple personality disorder. But I beg to disagree - it's simply part of being a professional. And, I gotta admit, it's also a bit of fun.