Those who actually consistently make money daytrading (averaged out over a long enough time period) don't have a need to write those books (and potentially put themselves at a disadvantage by doing so) to make money.
While those who write "daytrading secrets" books typically make heavy majority of their money from those books, because they cannot make money from actual daytrading.
I thought so too but it really can work if you have the right emotional mindset and stick to your game plan. There are streamers who do it live to prove it.
Those who actually consistently make money daytrading (averaged out over a long enough time period) don't have a need to write those books (and potentially put themselves at a disadvantage by doing so) to make money.
While those who write "daytrading secrets" books typically make heavy majority of their money from those books, because they cannot make money from actual daytrading.