Yeah I've been using the same 1994 Model M (M13 -- all black with a built in trackpoint) since... about 1995. Besides some dust build-up and me not having replaced the trackpoint nib and it being worn down it's still in mint condition.

Sure, they _could_ be built more solidly but I'm going to take a wild guess that 25 years is well beyond the lifetime a typical keyboard would be engineered for so it's probably still/already overbuilt.