The authors will do okay; unlike the people who read their books, they at least have produced something tangible for a return. But most of the readers of most of these books (a majority of a majority, yes) aren't going to rake in shit, because they are trying to do as the books tell them to do: get paid without producing shit, without even thinking. (Hm ... they're not even thinking.) And people will continue buying them until the inertia of hope runs out.
Without apologies--I've heard too many self-styled "entrepreneurs" claiming they're going to make a fortune through smoke, mirrors, and bullshit. (Most of them tap trust funds.) They actually believed this gravy train would continue forever. They might as well try talking to the dead.
When the aforementioned inertia of hope is gone, I think we'll see an upsurge in self-help books as those who were coasting along on fantasies desperately seek a new magic trick.