Everything from your x64 CPU to microSD to credit cards(not the readers; readers run antiquated Android and soon known-bad Chromium) runs some form of weird slow proprietary RTOS. It is what it is. I bet it takes ~century with help of superhuman AI to make those run an open and verified code. The situation is improving too, slowly, because using buggy proprietary code is not a goal, but means.
It's ok to be disgusted about the status quo, but that is not necessarily worth your time; IIRC one of original complaints by RMS on the state of software freedom that lead to Free Software Movement was about some HP printer running buggy custom OS. Even the point people said enough is enough goes back that far.