Yet every box of the upper tier ammo options are gone in hours once availability is known. I find that interesting.
I am not disputing your point, I can't help but wonder if U.S. manufacturers lack the expertise, ability, desire, don't care for reasons you mentioned, or lastly an accounting decision.
Then I think about why my old Ruger Mark II pistols seem to shoot everything well. Not just one of them, but all of them. CCI SV, Blazer Brass, even old Remington GB & Browning ammo. Federal Auto Match gave me terrific groups. Maybe it is the firearm?
My CZ455 seems to do the same as my Rugers. It doesn't care what it gets fed. Do the "better" ammo brands shoot better groups? Absolutely. The competitors need those improved results and consistency. I do not. I enjoy having the opportunity to compare the upper tier ammo with "lesser" brands, but as a rule the results from the higher cost ammo does not offset the cost difference and results from cheaper brands. Again, for my purposes. An example would be a group shot using Eley Tenex out of the 455 of 6 rounds shot a really tight .193" group tossing aside the one I know I pulled. Blazer Brass shot a .258" group if memory serves me correctly. I'll take the Blazer Brass all day long at that cost difference. But again, I don't compete and that difference is a loss for the competitors.
Lastly, the competitive shooting market seems to be growing and I think it is time for some U.S. manufacturer to step up and produce an equal or better offering than anyone else's.