In 2004, my model building work exceeded my museum director's salary (which was not chump change either) thanks to some large insurance restorations and repairs. It was a banner year for me. Yes, it can be done...but unlike a regular job, there's rarely a steady stream of work coming in to keep you busy all the time.
You couple that with doing work for customers on subjects that you often times have little or no interest in (I repaired a cruise ship model, yuck), and add in unrealistic deadlines and conditions from the client, and it doesn't make for the happy idealistic dream job we all wish we had.
In order to make a living at this, you need to offer something that the consumer can't find anywhere else, cheaper, or faster. Therein lies the problem. I still do alot of commission work, but the aircraft and armor side of the business has dried up because of the influx of die-cast models and pre-builts onto the market.
A customer wants a Tiger I from me, with all the bells and whistles, he's going to be charged $750 to $1000 for the model. In the day, that was my rate, and was selling alot of them. Today, you can purchase the same kit in a pre-built for under $200, and from 3 feet away, it looks just as good as my $1000 model. It doesn't take a degree in finance to figure that one out. The average person is not going to spend $1000 on a model tank, but it took me almost 15 years to establish that client base. These were people who had more money than sense (in most cases) and wanted things that were unique. Does it mean I'm a better modeler than anyone here? Not at all. It just means that I had a client base that recognized what they were buying and were willing to pay for it, the same way people will spend thousands of dollars on a piece of canvas that someone has splattered paint on called it 'art'.
Although I did as a full-time for about 2 years, I don't know anyone else who, as a one-man operation, builds full time to feed his family or pay his bills. Most guys either produce kits or have a real job to pay the mortgage. Even during the time I did it, the building wasn't fun. It was work.
Just something to consider, that's all.
Jeff