Well, you know what i meant. I can agree with your 20%, but not with your 30%. I think it would 've been much more than that. But we understand each other :-D
He wasn't necessarily listing riders, the way he said it, it was basically "it doesn't matter who i would compare him to, they all come up short". Literally he said "the Mathieus, the Julians, the Kaspers" all in plural. Meaning "Mathieu and guys like him, Julian and guys like him..." etc.
As for your comparison with BBT... If you want to compare those efforts, you might want to check the time differences they both ended up with. It's a constant with Mathieu's solo attacks. he goes from far, but at the finish, he is nearly caught. Be it in BBT or Tirreno, it's a matter of seconds. With Evenepoel, it's the opposite. He rides away, and then rides further away. In Germany the peloton needed ridiculous motorpacing to bring him back after a 90+km solo and even Nibali and Thomas themselves started pulling the peloton. In San Sebastian he basically wrecked Movistar and Astana. In BBT (Baloise Belgium) he simply rode Campenaerts off of his wheel. In Adriatica Ionica, he simply rode Masnada off his wheel. In Poland he made fools of all the favorites, ditched them with 52k to go and finished minutes ahead. But i'm not going to go any further into that. Mathieu is great at what he does, but he will never come close to what Evenepoel does. And the same goes the other way around, Evenepoel will never be able to do what Mathieu does.
He has the capacity to do that, but he won't do that unless he really needs to. In Burgos, he rode away at 2k from the finish. The first day, he actually tried to go from far, but the team told him to sit up. In Algarve he attacked at 500m from the line and put the competition away in the ITT. You can do stuff like that in a 1 week race that doesn't matter that much, but to do that in a GT, where efforts like that will come back to bite you in the ass down the line, is not so smart. And i think he will only do that if he really needs to, to go all in. Go for broke. If he needs to make up 3 minutes in the final week, and he thinks he has a shot to TT away from the group of favorites on rolling terrain, he'll go for it. He himself mentioned the way Froome won the Giro in 2018.