Deep down everyone knows what they should be doing. Eating better, exercising more, spending a little more time on the things they love and a lot less time getting that quick dopamine hit.
It's the execution that's really difficult. The quick fix from seeing a massive asshole publicly owned by Greta Thunberg before being arrested, eating some tasty but nutritionally bankrupt carb-laden food, or buying that thing that isn't needed but is SO NICE. Most of us are very bad at thinking ahead to a life that is better overall but means quitting that instant gratification.
It's not the content of a book that tells you the things you should be doing that might actually make you break the cycle, it's the ritual of buying the book, feeling hopeful, following the plan, and just maybe seeing some results.