It's not a sensible thing for a writer to develop a fondness for money. Money is like raging alcoholism: it's one of those things that only a few writers actually have but most people associate with the writing life.
On the other hand, it's absolutely possible for a decent writer with a love of hard work, an entrepreneurial spirit, and high-speed Internet access to earn a good living.
Most writers who fail at this have either not persevered long enough (and it's one long dry marathon getting started as a writer) or they don't develop a sound business sense.
A sound business sense means understanding that writing is not about art work, creativity, or expressing yourself. Join a quilting club if you want to do that kind of thing. Writing is about earning a living and possibly saying something useful, although it's important to keep those two items in that particular order.
There are lots of writers who insist on writing only what they want to write. You can't run other businesses along that formula, so why should writing be different? For instance, if I want to make peanut butter sandwiches and sell them to movie stars for a million bucks each, that's a noble dream but it won't fly as a business. I can want it till I'm blue in the face, I can say affirmations, I can chant and moan and visualize it and write a business plan, but it is not going to work.
A long time ago I met a woman who asked me about writing advice. She told me this: I want to write about German immigrants of the 19th century who settled in Fayette County, Texas. I told her to find another career. Now you might be able to write something on that subject (there are a lot of Germans in Texas, for all you non-Texans reading this) but it would be more like a thesis or an article you could give away to some local heritage society. You can't make a career around this.
Many would-be writers are stubborn. She said that was what she was going to write about. She only came to me to find out how to make money.
You make money by selling what can be sold. It used to be that you sold your writing to businesses (very lucrative if you do it right) and publications (newspapers and magazines). Last I heard, nobody is clamoring for articles on 19th century German immigration to Fayette County. But learn to write about medical technology or the latest movies or economic trends or learn how to do a killer interview, and you could sell some work.
The big shift in my lifetime is the imminent demise of the traditional publisher (sorry to break it to you this way). Anyone can publish a website (which is really just an electronic magazine), a blog (electronic newsletter), or even a book (vanity presses which are now just called digital printers). Magically, we all got promoted to be publishers.
Unfortunately, being a publisher is even harder in terms of mindset than being a sales-minded writer. You can do a blog on 18 cool things my dog can do but nobody wants to read it. You need to marry content with market.
And that's where most non-earning writers fall flat.