I sure don't think I would ever consider sharpening as a business. It just has too many variables. I know many make a good living from this, it just isn't something I want to do...
You would have to become proficient at all styles and types to make a decent wage sharpening. You couldn't pick and choose what you would take on, businesses can't work that way.
So, I try to keep my knives sharp, the way they should be to be useful and I do that at my leisure. I do sharpen for family and friends, if they ask. Sure don't want a career at it.
I'm not sure whether I will, either. But I'm set up to sharpen just about everything except chain saw chains, and if there was a market I'd probably do that, too.
However, I disagree that you can't pick and choose what you sharpen. I have a friend in WI that does almost nothing but high end Japanese kitchen knives. He gets $20
per inch and turns people away! He's obviously an exceptional case but it shows what's possible. I could probably build a pretty nice cottage business doing just kitchen knives. Already it's been suggested by one of the corporate chefs that they should have me sharpen for the company, and I already do sharpen for many of the chefs. Heck, I still sharpen for our old Exec and Sous that left the company.
This is an interesting thread. I am amazed that there could actually be commercial possibilities for knife sharpending. What is next - a shoe tieing service?
Putting an edge on a knife is so easy, although I am not all that great at it, compared to some who are really on the cutting edge of this activity. It is a nice relaxing activity to pursue when you have the ball game on the tube during a quiet winter evening....
I think you're missing an important point. Not everyone is capable in sharpening their own stuff, and many are not interested in learning. I know a lot of home cooks that will never see a sharp knife except when they buy a new one. Even many pro cooks aren't very good at sharpening. Certainly a hunter or outdoors-person should learn to sharpen probably but not all do.
Time is another issue. On my belt grinder I take a couple dozen extremely dull knives and bring them up to shaving sharp less than half an hour. When I'm done with a good Japanese kitchen knive it will push cut TP and treetop hair. This takes time and a bit of gear that most people don't have. For instance, I have a Japanese natural polishing stone that's 2" x 4" yet cost me almost $200. It finishes to somewhere around 60,000 grit. Can you get a knife sharp without it? Yeah, of course. But having a good assortment of tools really helps. For instance, I have a 140 grit Japanese Atoma diamond plate for repairs and reprofiles. I'd estimate that it cuts perhaps 3X faster than a DMT XXC. The belt grinder is one of the biggest time savers, plus it allows me to do stuff I wouldn't even consider by hand. For instance, last winter a coworker brought in a cherished Winchester skinning knife for me to try to fix. Literally the last 1/2" of the knife was simply gone- I don't know how he managed it but it snapped right off. I explained that I could fix it but it would be different knife. Since it was useless without any type of point he asked me to try. My approach was to draw a new knife with a sharpie, then use a 60 grit ceramic belt to remove everything below the line. Then I sharpened it up for him. He was pretty amazed, and I'll admit it turned out pretty well.
Many people just want a sharp knife with no fuss. For those people a reliable sharpener is a good option.