They’re essentially uninteresting.
By pure definition:

Don't misunderstand. Following the routines of famous people is interesting, to the point of being an oddity.

We love to know how writers write. How creatives create.
What was their magic formula for creative genius?
What was their way fo seeing the world?
Stephen King's Pencil.
Neil Gaiman's fountain pen.
Ernest Hemingway's notebooks.

Leonardo DaVinci woke up mid-day and made a list of everything he wanted to learn for that day.

Most of us wake up a lot earlier and stare at our phones.

We love to read about tools and processes and routines because that's the easy part.

It's much more difficult to find a routine of our own.

A routine that lays the foundation we need to go and make.