I’d be willing to bet that in a blind test that there’s nobody on STW could tell the difference between Deore and XTR on the same bike.
I can 😛
I’ve tried some old truvative square tapers, RF deus and XTR back to back, you can feel a difference between all three. It’s less that the lighter/cheeper ones feel flexy, and more that the XTR feel stiff if that makes sense, both in terms of not flexing and transmitting more buzz to the pedals.
Also got carbon cranks on the road bike which feel totaly different again, stiff like the XTR, but not transmiting vibrations like metal cranks.
So you might not be able to say “this bike has XTR” without a back to back comparison, but you can feel a difference.