What's more inefficient: the extra electricity and water of older machines, or the extra waste, manufacturing, and shipping caused by shorter replacement cycles?

I know many people who have had to replace or service their "high efficiency" machines within 5-10 years, while many old washers seem to last at least 20 years without service. Given the electronics and specialty parts in the new machines, it seems doubtful that you could keep one of them in service for more than 15 years.