We have a miele. Parts have been available but you might be in sticker shock. We replaced the rinse aid dispenser and one of the racks under waranty. These were under warranty but would have been expensive. I think miele offers a 5 year warranty now so check it out

just curious - how old was your KA dishwasher - mine is 12 years old and I had it repaired recently - it needed a new heating element and it was readily available - same with my 12 year old KA fridge which needed a new relay. If you haven't already gotten rid of it, should check on websites like repairclinic.com to see if they have the needed parts.

Your experience could have happened with any brand. How old was this dishwasher? The more popular a part is and the more models it is used on, the longer it will be available. A heating element, like weissman mentioned, would have been used on all the models at the time, and probably across multiple generations, so you would have no trouble getting one 10-20 years later. Keypads on the other hand tend to be very model specific, and often won't even make it to 10 years after the model was discontinued.

>We're interested in Miele, Bosch, and other high-end appliances. Are they engineered to have field-replaceable parts? Are parts kept in stock?

Of course they're engineered to have field replaceable parts, all appliances are. But, parts availability varies on the manufacturer. Bosch and KitchenAid are better than most of the high end ones since they have open parts distribution for most of their models. This means that their parts are widely available through most suppliers. Most high end manufacturers use proprietary parts distribution though, which means they are available only from the manufacturer and ridiculously overpriced (especially in the case of Miele). Also, the high end manufacturers aren't really better about keeping parts available in the long term than mainstream manufacturers. It just isn't profitable to be selling parts that almost nobody will buy. So, overall I'd say high end appliances are worse than mainstream ones in terms of parts availability, both early on and 15 years later.