Take for instance washing machines. They aren't conceptually complicated from user perspective. More or less, they have well-defined configuration parameters. You don't need a complex model of a washing machine in order to successfully operate it by any stretch of imagination.
That is, unless you buy a modern washing machine... where instead of having separate controls for water temperature and time you get a single knob. In most cases it doesn't even have a line on it to show which direction it points. It's just a round knob you can rotate endlessly. When you rotate it, in seemingly random order the lights near cryptic icons go on and off. Even if you can sort-of guess what a particular icon might mean, you will have very hard time finding a combination of the desired temperature and time.
And this is not unique to washing machines. Try toaster-oven, or water boiler, vacuum cleaner, air conditioner... modern day household electronics have the most idiotic design in their entire history. And they aren't conceptually hard to use. People who came up with the interface made it unnecessary complex and convoluted. And it's not a one-of event. This keeps happening all across the board, different brands, different kinds of equipment...
My explanation to this is not that it sells better: I'd absolutely buy a washing machine with text labels instead of icons. It's some kind of bizarre trend where manufacturers think it's more "stylish" this way.
Hell, take modern furniture or bathroom equipment for example. There's a bizarre trend to avoid showing the screw caps. It makes installing stuff much harder and the final installation more fragile and suspect to accidental damage... and yet it's nigh impossible to find simple(r) alternatives which would be durable and easy to assemble.