Most motorcycles are junk at 100k miles. The wheel bearings are shot, brakes are shot, etc, etc...
Motorcycles are ridden much harder than cars are driven in most cases. They rev much higher than car engines, increasing wear.
Plus motorcycles are improving very fast, by the time you have 50k or100k miles on a bike, they have come out with much better new bikes, faster, better handing, safer with electronic rider aids. Time to buy a new bike.
And Harleys have improved a lot, with much better production quality than old ones.
They still don't compare to a Japanese motorcycle in power, handling, reliability or anything else. But, different strokes for different folks, I salute anyone that rides a bike.