I wonder if energy regulations make it hard for mechanical products since they don't have the flexibility of electronic components.

That's certainly possible. Same goes for water - I note that Bosch dishwasher have some sort of system that analyzes the water to see if it's still clean enough to use before using more. Clever, and a savings for water, but one more complicated thing to break.

Of course, I fail to see why most modern consumer products can't just be driven with a Raspberry pi or arduino. Using off-the-shelf parts like that would do wonders for serviceability.

I design embedded products for industry and usually prototype with Arduino and Pi-alikes before designing the final board.

A custom board assembly is much cheaper to manufacture. For instance, for a recent design, the only chip used off a full Arduino board was the microcontroller itself (and then in a different, smaller package).

Physical and electrical constraints are often significant. And that's before getting into all the issues involved with firmware and IP.

I love the idea of open-source (hardware and software) consumer appliances, but everything is stacked against it. Primarily economies of scale.

I think people will happy to spend a bit more on a standard. easily replaceable board(and electronic components are relatively cheap), for an expensive appliance, since it gives them some piece of mind.

Further more, standard high volume stuff usually sees much more competition and investment by chip companies, who are really the ones doing the deep r&d in this industry.