It seems as if almost no one does this work nowadays, especially in a reasonable time frame. Perhaps it's an opportunity for the right person to undertake this service. I can't help but think the country would support one or two shops that did good work.
Bill, please re-read your post and I think if you think about it you have answered your own questions. The key terms are "reasonable" hmmmm, what does that mean? "Opportunity", yep jump right in if you have $50K to $100K to just buy minimum equipment. And then there is the question do you even have the faintest idea what you are doing. Its not an easy task requiring much experience (This is not taught in school).
I understand you frustration but face it the world has moved on. AR15 barrel are use and throw away. (Classics rifles are the dying trend.) I don't like it but I am over 70 and anyone in this generation is going to depart nearer then furtherer.
Buy a new barrel or wait for the re-borer to get you job done