Story Structure - is it a straitjacket or a means to a liberating end?

John Yorke  in 'Into the Woods' How stories work and why we tell them' quotes from Guillermo Del Toro:.

'You have to liberate people from film Theory not give them a corset in which they have to fit their story, they lifes, their emotions, the way they feel about the world. Our curse is that the film industry is 80% run by the half informed. You have people who have read Joseph Campbell and Robert McKee and now they're talking to you about the Hero's Journey, and you want to f****** cut off their dick and stuff it in their mouth.'

"Guillermo Del Toro echoes the thoughts of writers and filmmakers, there's an ingrained  belief that for many that to study structure is implicitly a betrayal of their genius,  its where  mediocrities seek a substitute muse."

Yorke, I think, takes the contrary view and the book is mostly about said structure.  But it echoes my thoughts about people who say that there are only 7 basic plots in all the stories ever told in the world.

It always struck me as a useless bit of classification because you could say that all of Classical Music is based on these few notes on the stave. There are only 8 notes in an octave, and with sharps and flats 15 or 16 notes in all. But does this tell you much that is useful about Mozart?

So does it tell you much to say that Hamlet is based on one of the 7 basic plots?