It's a stylus and a line, a symbol representing writing. A stylus at that angle is how Edit icons are usually represented in iOS as well, so it has a visual similarity.
I won't say the new icon is amazing, it is too simple for my taste. I'm just saying, I understand why we're seeing this shift, and I understand why this icon is being used to represent Pages.
Are you sure it's not a symbol for a regular pen/pencil? But also, how is a stylus easier to parse then an actual pen from the previous icons?
And what's the line? Previously it was the drawing line from the pen, so it naturally stopped at the tip, but now it has a weird angled end and disconnected from the stylus.
And why are we seeing this shift to worse / more ambiguous / less differentiated icons?
I won't say the new icon is amazing, it is too simple for my taste. I'm just saying, I understand why we're seeing this shift, and I understand why this icon is being used to represent Pages.