This answer is as wide and varied as the thousands of writers here....their work, experience, number of years here, etc... STILL making money? OR FINALLY making money? Or just plunking along? I parrot Christin. "It depends."
If we are paying attention and keeping up with all the latest news and advice.....the truth is we all know what we need to do to make money. As a main goal or intention of one's writing, I am led to understand that HP alone is fairly tough. There are some long-sufferers and heavy hitters who I'm sure do quite well. They EARN that money, I'm also sure.
Then there are those of us who are pleased with being here, have a love and NEED to write and make do with whatever amount of money we're lucky enough to pull in. After 4 years here, I do clearly see that my earnings pretty accurately reflect my efforts. I think that comes down to it all being "up to us."