Interesting, I realized after reading your comment that I had mentally parsed the above comment as meaning "85% of users have every feature they need" (and presumably some non-zero but decreasing percentage of the features the others need), but looking back I see that's not how it's phrased. It does make me think more about how "40% of features" versus "85% of features" should be interpreted though. Even assuming that there's agreement on what counts as a single feature versus multiple related but separate features (which isn't a guarantee), should every feature be weighted equally? I could see it being more reasonable to weight features by how necessary they are or by how much they're used; is the ability to do something very basic that almost everyone needs like summing a range the same "percent" as something more esoteric (I'm not a spreadsheet power user myself so I'm not sure what would be a good example here, but maybe calculating a regression of some obscure function class)?