Cadillac has been a marketing arm of GM since the '30s or '40s and its sole purpose has been to increase profit over their lesser brands. They have not been engineered to be durable cars that were sold as taxis in Germany and luxury cars in the US. When GM tries to offer similar appointments or performance of MB the first thing they do is take the part and try to engineer cost out of it, which always cheapens the part and causes warranty claims and long term durability issues. GM always moves the cost to the buyer down the road. You can go to the '50s and see mechanical fuel injection issues, or probs with Corvair, or probs with nikasil in the aluminum engine blocks for the vega, or whatever part and era you want to name. That's not to say mb didn't have probs and they did have probs in the mid '90s when they tried to meet Lexus dollar for dollar and part for part.
When most manufacturers introduce a new technology they try to make it durable, GM tries to take cost out before its proven, but they still charge "early adopter" prices. Until GM puts better water pumps on, or radiators without plastic tanks, or better wheelbearings, or better a/c compressors they etc. etc. etc. they wll never be a World Class manufacturer.
