[James Everington]

Short story collections sell far less than novels in general; more people buy and read novels than short stories. So I hardly see how this stacks up. And there are skills in short story writing that are transferable to novel writing: sentence construction and the like. I don't see how you've proved there is a 'tendency' for short story writers not to be able to write good novels with a mere three examples; even your own post contains more counter-examples!

Not convinced. Sorry.