A number of things factor into this. Parts are getting harder to find, and dealer parts prices have become nearly prohibitive in the last two years. Major repairs on a W123 can easily exceed the value of the car, so they are rapidly becoming impractical to keep up. Issues are more easily diagnosed on newer cars, and repair work on them is more profitable. Skilled mechanics with solid experience on old cars are aging out of the marketplace. These all combine to make working on 30 year old cars a serious hassle for many shops, with little opportunity to make a decent profit, and business is about making profits.

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'79 240D