While I believe such a thing is possible, it certainly wouldn't be easy. The problem isn't so much the writing, it's the advertising. I could write 1000 hubs and still be making less than a dollar a day. Success, especially online, is measured by how well you can get your name out there and how well you can direct traffic back to your money making articles. So, for example, 10 really well advertised hubs could easily make over a dollar a day. It all depends on how willing you are to self-promote.