As an independant I was concerned 8 or 9 years ago that the end was near. My experience has been that after the initial EEC beginnings that the majority of manufacturers are building a very reliable system. It seems that most of the " check engine" light problems I have seen are the result of broken oxygen sensor wires or something similar.
On the couple of occasions that I pulled a dealership in to make a repair I made sure to be there watching and learning from the tech. I would then charge the customer for my cost for the service call (no charge for my labor).
It was mentioned earlier- but I will repeat it. About 95% of repairs have nothing to do with engine management. Hydraulic cylinders, brake jobs, water pumps- these are the money makers.

I would love to be able to pull codes. I feel that it should be standardized. But until then, for myself, it never turned into a problem. I am always open with my customer when I am having a problem -and they seem to blame the manufacturer not me- for the problem.