The other is parts inventory and availability. I was renting a house about 14 years ago and the washer from the early 60s finally broke, not the motor the belts or the pump but one of the timing gears in the clock like sequencer that ran the cycles. The landlord simply disposed of the old unit and replaced it with a new way less well built one.
I called tons of GE parts suppliers and they could not procure a sequencer. Now I would just 3d print the one gear that had worn out. :(
Another option to 3d printing (I wonder how well this works for gears on consumer-level printers?), is to print out the gear pattern on label paper, and stick that onto a piece of plexi glass. Then cut out the circular shape, and finally use a triangle file (along with a vice) to cut the gear notches, using the printed label as a guide. I did this once for a gear for an older Okidata dot-matrix printer used for multi-part forms.
I called tons of GE parts suppliers and they could not procure a sequencer. Now I would just 3d print the one gear that had worn out. :(