For the simple reason that there is no publishing industry.

This article — Is Print Really Killing Publishers? — makes the point very well.

There is no such thing as “the” publishing industry, only publishing industries.

“Digital transformation” is a chameleon term in the publishing industries. It can be about web sites, digital editions, apps, e-newsletters, or shiny new object of the week.

He’s exactly right. Any generic talk about “digital transformation” in the publishing industry is misguided and bound to mislead. Radically different rules apply to news weeklies, romance novels, art books, legal services, etc., and it’s very important for publishing professionals to keep things separate.

The fact that lots of paperback readers have moved to kindle does not mean that lots of magazine readers will move to iPad. Different rules apply.