Not sure about the US but in some countries this is regulated for cars. Companies are required to provide parts for a certain amount of years after discontinuation of the product.
It seems abundantly reasonable that a similar requirement be imposed for prosthesis. And it would also be very reasonable for the required period to be longer than that of cars.
So yeah, not forever, but definitely not a a short period either.
I had to buy a mirror for my 23 year old car on eBay. There ought to be a law /s
> Not sure about the US
I think this was something that used to be regulated but is not now. There's plenty of financial justification for supporting cars 10 or more years by making parts, since most last longer than that. For niche products that are practically one-offs, I can see where it might need to be regulated because the economics won't encourage it.