I get more, and better, work since I raised my rates. (I didn’t raise them 500%; more like doubled.)
Make sure you read into the second section of that article, however, where it talks about being able to deliver quality and expertise along with those bigger invoices.
Also, I still write proposals. I would never recommend abandoning that. They are, however, basically a project overview and spec with a rough timeline attached. I change a few paragraphs, and it becomes my working spec and contract.