You said - "Remember, the Uintah was built with a 80 degree curve on the 7.5% grade and ran that way until the Mallets arrived and the curve was reduced to 66 degree. The universal joints were beyond the 25 degree of deflection with those engines, and it worked!"
The curve at Morro Castle, on Baxter Pass was found to be to tight in 1904 for the Shay's to comfortably manuver. The curvature at this site was reduced to 65 degrees at this time, long before the articulated's showed up.
Also to the above points, conceeded (to me at least) the the driveshafts can work in this distorted state - but can't you conceed that it just might not be the most effecient configuration, and possibly be a maintenance headache in the years to come? I see your point if you are concerned about the financial expenses associated with "properly" regaging a Shay, that those costs might be thwarted if the machine runs "fine" with out new manifolds. But can't you admit that there was indeed a mechanical reasoning to replace them on certain engines over the years? "Stupid" may indeed, in your opinion, describe the decision to spend money on "unneccissary" rebuilding (again in your opinion). But it takes on an entirely different meaning when applied to the thought that this is a mechanical decision. My now deceased, depression born father, would have watched you buy new tires for your car and called you stupid - why, because he had kept every car, truck, and tractor on our farm going for years with free used tires from the local service stations that had been thrown away. Most people would say he was stupid, for depending on questionable tires for the safety of his family, and at the least the dependability of his truck, but you on the other hand were "stupid" for buying something that you did not "need". There has to be a reason (strength, dependability, efficiency, maintenance needs) that Lima built, sold , and distributed new manifolds, etc. for regauging Shay's. I do not know if every Master Mechanic ( or more likely, a penney pinching puke in an office) saw the benifits of adding different parts to these locomotives when they were regaged, but obviously it was done sometimes. Surely you are not saying that every one of those decisions to rebuild and use new parts from Lima had no merrits at all?