Being a full time Knifemaker is a very tough way to make a living! Most of the full time makers that I know, who's only income is from knives, seem to live "hand to mouth". I applaud those folks for their tenacity, but know it can't be easy.
The position of a full time knifemaker is as follows:
The full time knifemaker's income is totally dependent on others' disposable income. If people do not have, or perceive that they do not have disposable income, then the Knifemaker is not going to see/get any of it.
My plan to become a full time Knifemaker started when I reached the 10 year mark in my military career. I knew if I stuck it out until retirement that I would be getting a check every month for the rest of my life. About 3 years before I retired, the wife and I started paying off all our bills, and made a pact to never rely on knife income to survive. Today we survive month to month on my retirement check and her income. Occasionally we have to dip into the knife account to make both ends meet the middle, but for the most part the knife income keeps the shop going, and provides for some of those extra needs/wants.
Unless an individual has a solid long term plan, particularly in these economic times, going into Knifemaking full time, without an outside income source is just not a wise move.
As far as "other things", I think it's very important to be as diverse as possible. Not only in the knives you produce, but also by offering other items/services as "stop gaps" when things get slow with knives. I produce Damascus for other makers, Forging Hammers, Damascus writing pens, Grinder Platens, Jewelry, Teach Bladesmithing classes, as well as forging and heat treating services for a number of local machine shops. I've even gotten paid as a consultant for our local college, and for the State Arts Council.