> The ban seemed to make phrenology more popular, and it spread to other European countries.
Literally the very next sentence. Banning things doesn’t work.
Phrenology died out because it was openly discussed, debated, and debunked. If you are confident you can prove you’re right about an issue, you don’t need to ban anything, you just go ahead and prove that you’re right. When you start banning things people only take that as evidence that it’s some secret forbidden knowledge that threatens the existing power structure and they’re even more motivated to pursue it.
https://soundideas.pugetsound.edu/cgi/viewcontent.cgi?refere...
In fact in places where it wasn't banned it flourished.