True, you’d have to duplicate all relevant blueprint.
However, the solution I presented here: User permisions for specific page and it's subpages - #13 by texnixe, could probably help with just redefining specific blueprints for different users via a plugin, while leaving a common set of blueprints for all user roles in the standard blueprints folder.
Note that if a user guesses a page URL, I think they’d still be able to access those pages and you might want to prevent this via hooks.