Yes you can. Many do. Many don't. It doesn't mean that if you don't make money from online article writing that it doesn't work. It means you're not working hard enough.
Making money through article writing is not an easy get-rich-overnight opportunity (if there are any genuine get-rich-overnight opportunites at all! [I doubt it])
Making money through article writing is hard work - one must not only put in many hours of writing good quality articles, but one must also promote those articles in a number of different ways. Marketing one's articles can take up a lot of time - but making money from writing is a business just like any other, and must be treated as such.
What you put in is what you get out.