Books read by Gen-Z kids in the 2010s are made of popular series. Only a handful are still being made.
Harry Potter: 1997-2007 (7 books)
Hunger Games: 2008-2010 (3 books)
Captain Underpants: 1997-2015 (12 books)
Dog Man: 2016-present (12 books and counting)
Geronimo Stilton: 2004-2020 (100s books ;; Remakes still created)
Big Nate Books: 2010-2016 (comic strip ongoing since 1991)
Diary of A Wimpy Kid: 2007-present (19 books and counting)
I Funny: 2012-2018 (6 books)
Shadow Children: 1998-2006 (7 books)
Mr. Lemoncello: 2013-2024 (6 books)
Amulet: 2008-2024 (9 books)
Terrible Two: 2015-2018 (4 books)
Middle School: 2011-2024 (16 books)
Bad Kitty: 2005-2020 (15 books, then full-color concept ripoffs)
Wild Robot: 2016-2023 (3 books)
The One And Only Ivan: 2012-2024 (4 books)
The books made now for Gen Alpha and Gen Beta are about cultural diversity. Nothing really about sharing and playing nice anymore.
*Note: Books which are listed with end dates in 2023-4 are probably just one-offs which haven't been released since 2018/9.