I think it's a perception issue, yes.
For example, by the end of the old runes/mastery system, most high-level AD Carries ran Resolve (or whatever it was called) as their secondary tree. It's very easy to run Nullifying Orb in Sorcery. We also know that plenty of fighters take Resolve secondary for things like Bone Plating or Second Wind.
I think AD Carries are trained really heavily into sacrificing everything for offense, which is weird, since they're usually happy to dip into Ninja Tabi, Bloodthirster, or Phantom Dancer without a second thought. But they don't typically make this choice in runes.
It's not a ton of data, but Bone Plating has a 55% win rate as a secondary rune on Vayne. By contrast, her most-picked Rune in that slot, Biscuit Delivery, has 53%. Biscuits has about 20x the pick rate of Bone Plating, but there's still over 2,000 games to suggest that Bone Plating's power level is not just random chance. In an attempt to verify that, I looked at...
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