Miele 4XXX series was pretty much a disaster
First incarnation (4840) had all sorts of random issues. Detergent drawers popping open and refusing to remain shut. Internal leaking that would trigger WPS sensors shutting machine down. Even when fault was cleared machines often would not restart. Miele sales persons and techs were advising owners to "tip machine forward" to drain water. Yes, some 5'5 110 (or less) pound American housewife is going to manage that feat all be herself...
Overall the quality just wasn't there for 4840, especially when compared to the W3xxx series that came out at same time. Side by side comparison had many customers simply feeling the later was more substantial washer. And they were correct in many ways. For one the 4840 could only be loaded 3/4 full, while the 3XXX washers like Miele of old could have their drums loaded fully.
Miele came back with the 4845 which supposedly addressed many of the failings from previous models, but it was almost too little and too late.
Miele was competing with Whirlpool, Electrolux, LG and others in bringing uber sized front loaders to American market. Whirlpool did so with their Duet washers which cost considerably less than Miele's 4840 or 4845
Miele's other larger worry was that they made those uber washers just for mainly north American market. Sales were tried in Europe and proved disappointing as few households wanted such a large washing machine.
So for all the R&D and other efforts Miele put into their uber sized washer and dryer they needed substantial sales in North America to make go of things. That wasn't happening and they were losing money on units sold. Coupled with word getting out about poor reliability and service issues (like waiting several weeks for Miele to fix the things), they just weren't moving those huge washers.
As for the uber sized matching dryers, less said the better. Miele had nothing but problems and complaints (though not nearly as so bad as the washers), so in the end both of them had to go.
Only way for Miele to have made money on those units was to do something they just refuse; built a North American plant and stop importing entire built appliances.
In the end Miele split the difference; going back to the drawing board we now have the new W1 and Little Giant washers. Americans can chose one or the other depending upon their laundry needs.
Thing is Miele like Electrolux and a few others know very well how to build rock solid 18lb-20lb commercial type washing machines. They have them on offer all over Europe. Just like WP bought Bauknecht to get their mitts on some H-axis goodies.