I will say that the reason I don't hang out at tractor dealerships that much is that everything seems overpriced.
I certainly wouldn't expect any of the larger US companies and US/International companies to significantly beat the Chinese companies for the price on parts.
Sorry, some of these are baler parts....
I bought an older Freeman wire baler that I wanted to try a wire to twine conversion. Thinking that if I bought new knotters, it would be like buying a new baler. $5206.38 for new knotters, needles, etc. Yep, almost like getting a new baler!!!
The broken axle I had on the baler, the manufacture no longer made (seems to be a common theme).
I went to the IH dealer today. $50 each for little 1" bearings for my IH baler, which the baler took 4, but they only had 2 in the entire state (none at the local dealer, I guess I should have called in advance), but one of the reason I went to the dealership was that the parts diagrams weren't clear with what was actually included. Apparently most of the gears and other major parts for the baler are no longer available.
I asked for prices on a couple of 3" gears for my International 884 tractor. $650 EACH, for just the gears, which they apparently had NONE in their nationwide dealer network. And that didn't include shafts, bearings, bushings, and etc. No doubt buying the replacement parts I needed for the tractor (4x4 transfer case gears) would cost well in excess of $2,000.
Anyway, I wouldn't say that Chinese parts are any more expensive than major US brands unless on had a good part by part price/longevity comparison.
There are a lot of tractors in the USA between 30 and 50 years old. Do you expect parts availability for your target tractor once it reaches 30+?