There is also the (missing) requirement to make things easily repairable, I wouldn't mind at all to replace a "subsystem" if it was easily swappable and costed

There is also the (missing) requirement to make things easily repairable, I wouldn't mind at all to replace a "subsystem" if it was easily swappable and costed a fair amount and the old one was refurbished. Many years ago there was an Italian maker of (at the time CRT's) TV's which was considered on one side "cheap" but on the other "simple/indestructible" called MIVAR. Their TV's AFAICR were essentially made of 6 or 8 electronic cards/PCB's on a sort of backplane of connectors. You brought the (not working) TV to the (approved) repairman, he would open the back of the TV, identify which card had issues, and replace it in like 5-10 minutes, for a fixed price (depending on which card had to be replaced). Then the cards were sent to the factory where they had a laboratory to diagnose the issue and replace just the component(s) that failed, and these refurbished cards were sent back to the repair shops.