Isn't it important to look for trends rather than standouts? Just because JK Rowling, who is an extraordinary success story, made it doesn't mean others will, because otherwise JK Rowling wouldn't be extraordinary.
But then again, we will never know about extremely creative yet poor people who are struggling to make ends meet and wasting their precious mental energy on things others take for granted.
But that does not discredit the original point (to which I was agreeing), that being poor is not an impediment to creativity.