Lanes is writing specifically in the context of children's literature, in this instance. She certainly doesn't think of White as a failure at all, but that wouldn't be clear from me not-quoting-in-full-context-here (....and in all honesty, that same phrase rubbed me the wrong way when I read it too, but I'm giving her the benefit of the doubt (I *think* she's using it more in the sense of "goshdarnit I wish he'd made time to write more" rather than "he should have written as many books as Laura Ingalls Wilder") in part because she was trying to convey White's quirky personality (she talks about his "arrogant modesty" or somesuch a few lines later) and mainly because I haven't had nearly enough sleep and will take anything the wrong way even if it's just minding its own business. *rueful smile*

[There ought to be a prize for you if you managed to wade through that sentence, btw, but you'll have to take a rain check on that. Time for me to go home and crash on the sofa for a couple hours...]