You can get a commercial or industrial version of most appliances with relatively few features, and a focus on durability and ease of maintenance. One problem is commercial units are loud. The other is they are often slightly larger. For most users the cost alone means the residential versions are a better option.

I've wished for this myself. We replaced a refrigerator, and I thought "what a waste - 95% of the mass of that thing was non-moving parts that could've lasted centuries".

> There is still R&D to be done to update for modern manufacturing techniques, but an upstart that simply built old classic designs and added a 30-year warranty would do well. Bonus points for standardized dimensions (for easy replacement years from now).

Extra bonus points for publishing manuals and 3D printing plans for replacement parts and ensuring they remain available long term - eg, creating a web site and funding a foundation to keep it running + seeding torrents with the info.

> I’m really surprised no one has come up with a reliable appliance brand

Speed Queen has done this for Washers and Dryers. https://www.speedqueen.com/

I used to think the same thing, however looking at some recent reviews it appears as if Speed Queen has succumbed to the cost cutting movement. People are complaining that the latest machines no longer clean properly and are not up to the old standards. I don't know about the repair-ability of the machines but if they don't do the job they were built for then it doesn't really matter if you can fix it or not.

If you want reliability generally you want to go with the 'industrial' version - which may or may not be ideal for whatever you want to do.