Far as I can tell...
The problem is not strictly with the machines, or with miele as a company, rather with their status in the US market.
If your average repairman the likes of which would be more than capable of repairing a whirlpool, kenmore, GE, Frigidare etc could work on a miele equally as easily as they can here, then you simply wouldn't need to deal with miele directly. The pricing and lack of enthusiasm to repair a unit is what you would get if you went directly to the manufacturer of almost any appliance, because it simply isn't worth their time. As it is these machines are a niche purchase over there, so most repairmen I'd imagine have never seen one, let alone would your local appliance repair shop stock the parts!
It's much the same as trying to buy parts or get repairs done on a filter queen vacuum in the uk. They are sold here, but I had to order parts from America at a highly inflated cost for the one I got on eBay, I never managed to acquire all the parts I needed so gave up in the end! However our American cousins speak very highly of them!
It also helps that the most basic Miele washers come with a 5 year parts and labour guarantee as standard, and the mid-high end models a free 10 year parts and labour guarantee!
Matt