Well, That Depends
Upon what you consider the useful life of front loading washing machine.
Miele boasts (at least as far as their older models are concerned), some of the longest, if not the longest life span. While the oft used quote is "twenty years tested performance", what Miele actually means that under tested conditions (about two or three wash loads per day), a washer of a vintage period should last on average about twenty years.
However in your case, as probably many others whom have purchased used Miele units, the conditions of previous use are known. Constant over loading of the washer, use of wrong and or too much detergent, and or other forms of "abuse", would cause parts to wear out sooner than they should.
From what one has read on various European washer forums, lower final spin washers tend on balance to out last those with speeds >1200.
The 1900 series was Miele's first with spin speeds at 1600rpms. As noted upthread using high speed spin speeds with unbalanced loads more than one should, is going to have an effect on some parts.
My guess is somewhere in Germany at sometime, someone sat down and ran the numbers. How long should bearings, seals, shaft et al other parts last under "normal" condition, cost of repair (if parts go under warranty), expected duty life cycle, and other factors to reach a number for making part specs.