I'm not sure what you are trying to say here, or if you are trying to somehow diminish my statement by somehow claiming that online documentation is causing the same magnitude of harm compared to using a book?

Two things:

1 - I agree with you. A good printed resource is incredibly valuable and should be perfectly valid in this day and age.

2 - many resources are not in print, e.g. API docs, so I'm not sure how books are supposed to help here.