Oh Fred,
Don't you know anything made these days is NOT meant to last more than 10yrs. Forget 30-50yrs
The subject keeps popping up on this thread, and I have to throw my two cents in as well. I do believe that the huge proliferation of models and frequent changes by manufacturers is all about preventing another "8n situation" from occurring. Parts sales is a legalized crime as long as they can keep the tractors different enough so that no 3rd party can jump in and mass produce parts. Case in point, literally is CNH where Case and NH have identical tractors with parts made just different enough to not be interchangeable. There is not now, nor was there ever, a need for manufacturers to make 10-12 different models of small tractors at a time. It gives them the APPEARANCE of offering product diversity while assuring that they control the parts stream in the future, and can END it when they so decide.
Here's a smaller scale example: I own an Echo CS500VL chain saw, about 35 years old. It works as well as the day I bought it, but it had no chain brake. They had one available for many years, but it was expensive and I put it off. I finally decided not to use the saw unless I could get a chain brake, but they stopped making it. So, I bought a new saw. CS600P. Of course, shortly after the new saw arrived, I found the chain brake for the other saw on EBay, so I bought that too, and put it on. OK, so I'm out some cash, but I have 2 good firewood saws I can play with, right? Only guess what? Echo stopped making both sprockets AND air filters for the old saw. Now, this goes back over 30 years. Now, forget about it. You take care of a tractor today and make it last, and you're going to pay for it in the end with outrageous parts prices, until they decide to put you out of it, and it won't take 35 years!