There are many reasons for delay in delivering work, some valid, some not.
I have observed over the years many gunsmiths who have gone out of business. Here are a few of the reasons:
1. Spending time BSing with customers rather than working on guns. Hire help for the front counter and work on guns.
2. Taking on idiotic jobs like working on junkers whose value is far less than the cost of the work. (The customer will refuse to pay the bill.)
3. Getting involved in a customer's "project". If the guy wants to convert his .32 rimfire Tramps Terror to .454 Casull, let him; don't waste your time on silliness.
4. Breaking/losing parts and having to order or make replacements.
5. Tackling a job without knowing how to do it. These are usually self-taught smiths; schools teach at least the rudiments of most jobs.
6. Not having the equipment to do the job or not knowing how to operate it.
7. Farming out work to other gunsmiths or to large specialty shops. Not only is the smith at the mercy of others, if the customers catch on they will simply eliminate the middle man and go directly to the other guy.
8. Failure to understand even the rudiments of running a business; the worst in this respect are the gun hobbyists who can get immersed in a discussion of Victory Models when they should be working on guns.
9. Failure to post and keep regular hours. One smith had his shop in his home and a pretty young wife. Customers found the shop door locked for hours in the middle of the day. Soon they didn't bother to come back.
10. Sheer ignorance or stupidity. There is no licensing test for gunsmiths, so some folks think all that is needed is an FFL and a few hand tools. They screw things up badly and the word gets around. Worse, they create a dangerous situation and someone is injured or killed. The result is bankruptcy or even a prison term.
Jim