Why Americans...
...were ahead of Europe in home appliances and other things for much of the 20th century.
Had 20th century history panned out differently, who knows what could have happened and who would have had what when. Europe, during the first half of the 20th century, had some pretty intense existentialist issues to deal with. WWI & II significantly affected social and economic progress there. Economies and industrial infrastructures had to be rebuilt and that took time. Europe also suffered a significant brain drain before, during and after WWII - which benefitted the US greatly.
The fact that America was a meritocracy from the word go and far more enthusiastic about embracing new ways, led to a wealthier and faster growing middle-class than in pre-WWII Europe. Even Charles Dickens noted this during his travels through the US in the 1800s. It's a cultural thing.
Let us not forget that after WWII America was intact and able to crank up its own domestic economic growth and development instantly.
Other issues like access to resources, space, good, affordable housing, sanitation, economic growth/policies, social stability, access to education; all of these contributed greatly to the fact that American housewives were able to enjoy appliances before their European counterparts.