You might lose your big job to someone in a third world country who will set up your spanning tree remotely for $10. Then when you have to start selling firewood for a living, you're going to run into cheap folk who don't want to pay a "dumb country boy" $100 per cord...
This thread is getting derailed...
Just as the sharpening shop is pricing themself out of work, so too are many of us. Lots of jobs moving overseas or simply disappearing. In my present job, our IT department has been cut from 5 people to 3, then to 2 before my boss quit, leaving me by myself. Can't see how they can move my job to India but then one never knows...
There's no market here for firewood cut/split/delivered when a load of logs cost $100 per cord. Based on how much the kid grinding chains makes, I would have to sell a cord of C/S/D firewood for $500. I think the price would be over $1000 a cord at my rate of pay. I would be better off to buy a grinder and go into the chain sharpening business since there appears to be a proven market there.
Anyway... to try and drag this thread back on topic... as others have said, there are guides you can attach to a file that work like training wheels. Hand filing is not difficult. You just need to understand the angles and have a bit of manual dexterity.
My father (God rest his soul) could never file a saw chain his entire life. Couldn't sharpen a knife either and he was a butcher by trade. Every time I went to visit him, he had a dozen dull chains for me to file. Try as I may, I could never teach him how to do it. Personally, I think most of those that can't do it, don't really want to do it.