I've kept all my original parts also regardless of condition because if the car goes the parts can remain with it.
Technology moves quickly which should keep some odd parts available like you said if someone is already 3d printing washer jet covers how long before someone starts making 3rd brake lights?
I understand you. A number of times over the past few months I've looked at parting ways with mine, however I cant find a worthy replacement and I'm too attached to mine to let it go regardless of what it may need in terms of repair.