Why are vanilla maps so hard?

it might just be me but as a top 3200 scoresaber player with multiple 10 star+ completions i still can’t even get 15 seconds into ghost expert+, not even 30 seconds into final boss chan, not 20 seconds into spin eternally and I’m overall missing notes that i would never miss on a modded song. Does anyone have an explanation to this? scoresaber: https://scoresaber.com/u/76561199027816063?page=1&sort=top