@Drover , you are probably correct about being able to advertise low annual servicing costs. That would also be relevant to the life or reliability of engines and transmissions. You can always use the cheaper oils and lubricants and get away with that if operating in optimum "light" conditions, but in real life situations, there will always be times when one is operating outside those limits, and there is a need for a higher reserve of wear protection.
The days of straight forward and easy oil and transmission changes by the home DIY brigade seem limited. There are a lot more complicated instructions and methods for even changing engine oils for some vehicles. I remember seeing just recently that engine oil should not be left to drain for more than 30 minutes as this causes an air lock on the pickup tube which meant that the oil pump did not work on start up. I think it was a Ford Ranger??????? Something to do with the shape of the pick up tube leading to the oil pump. So one has to be careful when working on our modern sophisticated machinery. Gone are the days of draining the oil from the sump after a long hot run and letting it drain all night, before fitting new filter and replacing oil next morning!!!
I agree with you on how "unclean" electric motors are after long periods of use. It is amazing how much black static dust is attracted to electric motors during normal operation. Even smaller ones used in protected situations. How are they to be serviced and cleaned (if necessary) after years running in all conditions of heat, dust, moisture combined?? And all the sensors providing precise information to the computers? But that is "progress"!!!!!!