Here is one of Alex Hallett’s Arctic Circle cartoons about appliances and energy consumption:

It probably is the case that the eco setting does not do a lot when you look at the Big Picture.  Also, how often does it actually get used?

New power stations and fossil fuel emissions are the two big environmental effects of electricity generation.    Here in New Zealand something like 70% of electricity is from renewable energy sources which means carbon emissions per kilowatt/hour is not as bad as other countries.  In recent years plans for at least three major hydroelectric power stations were scrapped for an assortment of reasons, and this may well be the trend in the future.

Another consideration is the environmental effect of discarding older models without an eco option versus buying a brand new one with it.