Could not disagree more strongly. Choice is always better than a lack there of, and as others have pointed out, I think you are over simplifying the history of fly tying. Nobody can force modern tiers to use any new materials, and substitution is always an option, no matter what some commercial tier might insist.
And with regards to "historically available materials" do you mean like Bustad, Condor, Eagle, Heron, or Stork? How about the original dubbing for Tup's Indispensable? Chadwicks 477 perhaps? Not all examples of materials used by Catskill tiers per se, but illustrative examples nevertheless.
Seems to me if you think the debates about the different materials are unique to today's tiers, I think you do not fully appreciate what an opinionated and picky bunch fly tiers actually are.
P.S. If you have no use for your 'old' Metz capes, just post. I'm sure you'll find no shortage of volunteers to take them off your hands.