Unfortunately, the truth is somewhere in the middle - the highly publicised banned books do see growth in sales, it is the unsung banned books that quiety get forgotten.

Pareto principle.

Just like with home security, it is enough to add friction to get the majority to look at easier options. If they can switch out the sanitized (boy in striped pjs) versus the directly confronting (Maus) then they have succeeded, with far more insidious moves never seeing the media.

Alberta tried to wholesale copy a bible belt curriculum for our schools, with actual educators universally in horror once they saw the content. As well as anti-science materials, and eradicating sex education outside of "abstinence" (which is proven to create more unwanted pregnancies versus actual family planning) it has things like pushing so-called societal benefits to the slave trade, etc.