I doubt very much that the blue pill/black pill boards are produced in anything close to the volume of most consumer products like washing machines. Those "mak

I doubt very much that the blue pill/black pill boards are produced in anything close to the volume of most consumer products like washing machines. Those "maker" boards are dirt cheap because (a) the builders can use gray-market parts, including "pulls" (b) there is nothing on the board that isn't absolutely necessary: even the PCB itself tends to be 0.031" FR4 instead of the more robust 0.062" to save money. I've seen some boards in the Arduino ecosystem that clearly used punched holes to save money over drilling. When you're building tens or hundreds of thousands of something, using a baseboard and daughterboard architecture is going to be far more expensive than putting everything on one board. Hell, I'd go so far to say that if you're building more than 500/year it's not worth it.