I hate circuit boards in appliances with a passion.
I am an electronics engineer and circuit board designer, and I get a lot of insight on how things are made now. In short it is pretty sad, and re-enforces why I buy or keep vintage stuff as much as possible.
Given that most of them are made in China, the factories there usually have the freedom to substitute in the cheapest parts they can find, as long as the specs are equal to or better than designed. This is easy - anything can be written... However there are no real measures on the quality for parts that are not rated for military, aerospace, or automotive. So whether it may be a flashlight or light bulb or a built-in oven, the discrete parts quality can be the same. And a failure of one cap in a board with 500 parts, can render the whole board 'bad'. Even appliance techs will not troubleshoot a board to component level, and they are not allowed to. They have to replace the whole board as spec'ed by the manufacturer.
Now the manufacturer is the one to choose how long boards may be available, if at all. Luckily Carrier still had a factory control board for my 25 year old furnace that I had replaced a few years back after it developed a hate for the cold.
A few years back I had to replace a cap on the board in my 25 year old GE range as it caused the timer beeper to constantly squeal. Luckily the board was only for a clock and timer, not for gas controls, as it was discontinued.
Brand does not mean quality anymore either as the boards are subcontracted out.
I scavenge stuff from the curb to see if there are simple fixes so they can be donated or sold. Build quality is pretty bad from what I have seen. Even JBL, bose and Klipshe use cheap off-brand caps that fail prematurely. Some models even used off-the-shelf self-contained amp chips like one would find in a TV or car radio. TVs have similar issues with caps and LEDs in the backlights - one goes out, the whole string does. Microwave magnatrons do not get proper cooling. I can go on and on........
And just when I thought that something could not be made cheaper and/or worse, they are.
When going through some new houses under construction, I noticed all the water heaters were tankless - very complex control boards in those. A complex HVAC damper control unit was used to regulate the upstairs with the downstairs temps. Lets not forget that the heatpumps and the air handler and thermostat have control boards also.
The fireplaces were remote controlled, so that means control boards there in a hot area.
Even the bathroom exhaust fans all had DC brushless motors for energy efficiency. I bet the caps in the control board will fail in 10 years, and the units have to be replaced. I have never had an AC bath fan go bad. Maybe every 30 years I would take one down (they unplug) to clean and oil it, thats it.
Energy efficient stuff is not specifically designed to save consumers money in the long run (although it can unintendedly), but to just collectively save power off the grid so that it can be wasted in new places.
I would hate to see what a lightning strike would do to a modern home...
And those with gas and appliances that are electrically controlled will be in the cold in a power outage.
During a recent 4 hour outage I still had hot water, a stove, and a gas unvented fireplace.
Time for me to get off the soap box now and burn it for heat...