when I thought along the lines of a "consumer" in the old days, I too thought this way
but - there is simply more to the issue than this...much more
prop blends were created to shield the design and specs from competition in the industry -- an industry long rife with copy-catters and sneaky generics who try to horn in on other companies hard (and expensive) efforts of R&D, and try to ride the back of a formula that is already popular by offering it cheaper then the genuine article -- because no money/profit needs to be built in to recoup those initial development and research costs
once you see the bigger picture, the idea that a company does it purposely to somehow "cheat" or "fool" the consumer, seems rather silly