Would the search for reliability drive alloy development or design to reduce reliance on fancy alloys or most likely
GE used cobalt-chromium-molybdenum-tungsten alloys for the '30-40s turbochargers. It's harder than Nimonic 75 to work with, but overall, Stellite 21or 23 was just as good as Nimonic 80 the UK started using in 1942, that was better than the early stainless steel, then Vicker's Rex 78 alloy that Power Jets had used up to that point.
To me, it's as simple as Whittle getting some US alloys when he starts after reading what GE had been doing with turbos. The early versions of that alloy had been developed pre WWI.