He talks about what the consequences for not doing so have been for Zoomers and it is quite worrying: escalating rates of depression and anxiety, increased rates of suicide, fewer friends, even fewer close friends, reduced social trust, more on-campus violence, increased favorability to authoritarian policies.
[0] - He starts the book with a discussion of the title. He initially resisted it because people usually use the word coddled to blame the coddlees but this book very much blames the coddlers.