How many miles on a Ural before the bike is junk? Some would say 1, others would say never. I think they are what they are and if well cared for with proper maintenance and required fixes they can go a very long time, 100k should be easily obtainable. BigJame's rig is already at 75k-km or approaching 50k miles and he's complaining about how well his runs. And they can last virtually forever provided you accept "rebuild" as a normal process. They are designed to be repaired.
Consider old Ford tractors. We had a 601 Workmaster, always cared for, parts replaced when worn out, that tractor kept on going and going, it just never stopped and had thousands of hours on it when we got it, we probably put another 2000 hours on it ourselves. But, parts had to be replaced. I can't think of a single time we went to use it that it wasn't checked and something tweaked. Not always major, but always something. Float valves stuck so the carbs had to be cleaned, linkages wore out, wrist pins wore out, but do the work and it kept on plugging away. I can honestly say I have had to do FAR less work on this John Deere 4310 in the 600 hours on it than the same 600 hours on that 601 Workmaster. I'll also say, that Deere aint going to last anywhere near as long. The 601 Workmaster was designed to be reparable, this Deere is designed to wear out and recycle.
I now have 2 of these things. One now has 12k on it and was very well cared for by the PO and myself. The other I just got has about 35k on it, not so much as well cared for. Based on my first rig, as I dig into the second one I would swear it had far more mileage on it than 35k. It's clutch is about shot, it is noisier, shifts rougher has a tick/knock/something going on in the engine that gives me pause and needs a tremendous amount of cleaning (I knew it was not a perfect bike when purchased so not crying here). The point is, I can not imagine my first rig being in the same condition by simply applying another 23k unless I stop all maintenance, it just wouldn't be possible. If Ursula farts, I want to know why and I go fix it not just throttle up more and keep grinding.