Do you rather want your refrigerator, washing machine and coffee maker send all the data it collects about you during your usage to some company you don't even know? How is it ridiculous to want to be able to make your devices do what you want to do, not what the big company behind it wants?
1. A lot of those more recent machines do actually connect to the internet.
2. Since you want to run your own software on them, but you can't buy open hardware like that, did you build it yourself then as you suggested? "If they don't exist, make them yourself."
If people want to buy open hardware, then just buy those. If they don't exist, make them yourself.