First, marry a woman with a good job. Secondly, if that isn't possible, then work at a job for 30 years or more, retire, then make knives full time.
Actually, it is quite possible but it isn't as easy as it would appear. Plan on putting in 12 to 16 hour days, handling customers, paying bills, ordering supplies, keeping receipts, attending shows, joining the knifemaking organizations, network with other makers, get pictures made, go to Atlanta once a year, filing taxes, worry about health insurance, paying social security, etc.
Remember, making knives is only one of the talents required, selling them is another. The "name" makers not only know how to make a knife, they also know how to sell them. Selling is more than the gift of gab...you are also selling yourself.
JHiggins absolutely hit the nail on the head. It is not an easy task being self employed, each and every knife that leaves the shop takes a part of you with it.
Me? I have a good day job that I thoroughly enjoy. It is where I want to be right now. I am nothing more than a part time maker that enjoys making what I want to make AND I can tinker when I want. Full time? Not much room for the "inner artist".
To do it, it takes a given amount of passion...some have it, some don't. Only you can answer that question.
Craig