For now I will throw out the idea of making a physical product like a lawnmower or stereo. Sure someone could make money by producing those things but it sounds like a lot of work. Why? This economy seems to be a knowledge economy. In my city their are residences being built around the university and the college is expanding with new buildings. There is typically news of factories closing down meanwhile at the other end of the city millions of dollars is being spent on education. So of course if you want to be a dentist you would need a license, but what about if you want to start a business? No one has to go to school for 5 years to start a business they can just do it. Or lets say you are a plumber by trade, should a plumber limit there income to what they are paid hourly to complete a job. If the plumber starts his own business it will take some time and lots of effort to build up a clientele and penetrate a market with many competitors.
There are lots of benefits to writing a blog.