From the number of problems you have had it sounds like the first owner(s) of your car have used such rational.
How could any of us avise you to do less service than the manufacturer recommends?
Maintenance is what you do to maintain life in machinery. But let me tell it to you like it is. They build the cars so good now days that if your pocket book is more important than your machinery you can join the ever growing ranks of new car owners that do NOTHING. I firmly believe that you can drive a new MB 100,000 miles and do NOTHING.. Just add oil as it is used up.
Of course the next owner of that car will have bought a pile of junk.... does that matter to you? I image it doesn't matter to a lot of folk. Using that last assessment the ONLY reason to do anything on that car that you will trade at 70k is that you will loose an equal amount of money on the sale value without records of service. But then again records are probably cheaper to make than service for this type of car user.
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician