> Except these new efficient ones work very poorly.

I haven't noticed that at all. Nowadays in Europe most dishwashers and washing machines offer energy-saving cycles that do the same job, only 3 times slower. As far as I'm concerned this works as advertised.

We replaced a 20-year-old machine three years ago. And then replaced the replacement last year. And then we had about six repair calls on the new one. It's been good since about August, but don't say that too loud . . . it'll hear you and break!

I guess that to some degree that would depend on the embodied energy, but if they really only last a few years I agree (do not own a dishwasher myself because rented apartment).