Investment and trading books, articles and videos are made by people who might not actually be winning traders. They make their money by writing "investment materials" and sell it to us, the plebs.
This is 100% true and for sure a lot of writers or people who are writing some content about trading are really losing money on trading and they are just making money on these books or some are making money on affiliates like inviting someone to signup under their links on some exchanges and they will earn money via commissions.