Some perspective on 240V in US
The fact is, anyone in the US living in a single-family house or townhouse, with reasonably up-to-date electrical service, can get an electrician to install a 240V outlet for a washing machine. The cost would range from a couple hundred to a few hundred, depending on details of the job, and where you live. This is a one-time cost that isn't prohibitive. It's common to spend much more on home renovation projects.
So, notwithstanding all the discussion about why we have 120V while Europe has 220V, and how hard it would be to convert the whole country, 240V is easily available here, if people want it. The diminishing availability of 240V washers here just shows that people haven't been convinced to want it. There are also the Energy Star considerations, but I think those are a matter of tax credits, not outright prohibition of machines using more energy. So that, too, boils down to whether people are willing to spend a little more to make up for the tax credit that a manufacturer might lose by selling a machine that uses more juice.