Motor work for air-cooled Porsches has become prohibitively expensive in the last 15+ years. You talk to old-timers and a rebuild was 6-8k. Now it's 30-50k... If not more depending on the base motor and mods. Jerry Woods spec 911s are very expensive propositions now. 225k plus. It's a function of the popularity and upscale ownership.
Its also a function of where the industry is going. One of my neighbors when I lived just outside Washington DC was the lead mechanic for the largest Mercedes Benz dealership in the area. He left the job because the newly minted techs they were sending to him did not understand cars. They didn't work on their own cars, weren't into racing, etc. They could read codes and follow the "cookbook" that told them what to do with the codes, but they did not understand the basics (which mechanical systems were involved, how those systems functioned, where the weak points were etc.). They would follow the cookbook and then return the car to the customer, without checking if the problem had been resolved. It drove him crazy.
I remember years ago walking across the street to ask him a question about my wife's Saab's brake system. He said "which type do you have. There were three types of systems used on European cars in that era. One has this configuration; the second looks like this, and when you look under the hood at the third one you will see this. Which do you have?" I said mine looks like the second one you described. He replied "here is your problem."
The industry is not training guys like that any more, and most of the guys who have that type of training are at or beyond retirement age. And most of the independent shops who specialize in foreign cars used to hire at least some of the their mechanics from the dealerships, which makes running a small independent shop even more difficult. In short, prices are going up because the supply of people who can do quality work is going down.
