I think the policy is that they keep replacement stock for repairs for 10 years after discontinuation. Also for a key holder the main repairs would be stitching/glazing and the brass parts which they will always be able to do. I just got my 18 year old 6 key updated with a new rack and press stud - it looks amazing, they really last!
It all depends what it is that needs repair. I had a Randonee repaired a few years ago that had been discontinued for years. But it was black epi so I guess they could just fashion any spare parts even if they didn't have any.