This is all about the point at which a vehicle becomes 'beyond economic repair'. Just one example of this is companies that offer extended warranties on cars are writing vehicles off if they are more than a couple of years old and have had an incident which causes the air bags to go off simply because it is so expensive to reset them. The car is then sold on at 20% of it's market value.

With modern bikes there is so much non essential gubbins fitted, there comes a point where the owner may look at the market value versus cost of repair and decide that it's not worth the outlay even on a low mileage bike.

In a travelling situation you would obviously be better off with a simple machine that can be fixed at the roadside. If you prefer to use something full of technology, whether it's new or not is going to make little difference to the risk of a catastrophic failure which will be a serious hassle and expense to fix. Assuming you have kept up with the maintenance of the bike and replaced all the rubbish OEM components that were supplied as suspension with the new bike and you then suffer one of these catastrophic failures, replacing the bike is not necessarily going to be the most economic solution.

In summary, older low tech machines will go on forever, modern hi tech bikes could give up at any time and it's certainly not a function of mileage