[jdiff]

That's kind of a nonsensical suggestion. You can't define this in a way significantly different than it already is that makes sense across devices. You can use metrics like "% of performance vs flagship product," which a lot of people have used to point out that lately the xx80-class-turned-xx70-class cards of today are looking more like xx60 Ti-class cards of yesterday in relative performance, but performance isn't always that simple and there's no way any company will conform to it. Even if they use it, there's no incentive not to break from it the same way they do now.