If you're willing to work a hundred hours a week to move into the top ten percent income bracket, it is profitable.
Strictly speaking, you wouldn't be movin' on up. If your earnings per hour aren't improving then you're not really progressing, are you? You're just logging more hours. That's not profit. It's wages.
Use your dedicated work ethic to get awesome at something which you enjoy and which is billable. Being very good at or extremely knowledgeable about something means you can do the same job in less time than others, which makes you maketable, profitable, a good value, uniquely suited, sought after, etc. It doesn't matter what you do. Just be really good at it and leave your competition in the dust. Good times or bad, the early road is hard. Good luck.
Here endeth the lesson.