Re:long term costs for maintenance, seems like there should be a secondary market for 3D-printing replacement knobs, buttons, and related parts. No inventory needed. Especially if the knob designers had that in mind at the outset.
I would love what you describe. Producers would have to design and manufacture like this from the outset (like you said) but also open source their CAD files.
There's already a market for these things. But the prices are often crazy high because the supply is limited to the parts that people are able to get from scrapped vehicles. For example, see this $200 plastic radio bezel for a 1995 Toyota: https://www.ebay.com/itm/264805497008
