I'm aware Mortirolo isn't as steep, but at the time of its introduction, it was unusually hard (not the side Bugno went up in 1990, but the one Pantani entered the scene with a bang in 1994). The Zoncolan has entered a bit of a mythical status in Italy, because of its extremity, a ploy to show how Italian climbs are harder than French ones. And from this the Angrilu in Spain to publicize why the Tour isn't the only terrible race. It's pure marketing.Mortirolo is less steep than Zoncolan and Lussari, and it also serves as a point for long range attacks. That doesn't apply to neither a MTT or Zoncolan when it is a MTF. And I also think it is a difference between 10-12 % like Mortirolo (okay, it also has a short steeper section, but most of it is 10-12 %) and the last 5k on Fedaia and 15+ % like Zoncolan and Lussari.