How does the global diffusion of "Western" industrialism and media messages make native societies "better off" or not?

I would argue that they do not, but that is simply a
matter of opinion.

In the place where I grew up, the native
society was largely poor in material terms.  However, the society had always been that
way and the cultural attitudes of the people and their customs were adapted to this
state of material affairs.  Because of this, you could argue that they were "well off"
because their culture and their circumstances
matched.

During the time that I lived there, Western media
messages and Western economic expectations had diffused to where I was living and had
been embraced by many of the people.  Many became "better off" in material terms as they
came to have cars, TVs, and imported foods.  However, the coming of these material goods
and the expectations that were part of a Western economic system did a great deal to
alter the culture.  This led in many places to a large increase in youth suicides as
people were unable to cope with being pulled towards Western economic attitudes while,
at the same time, being pulled in the opposite direction towards traditional
attitudes.

In this sense, native societies can be less
"well-off" in social or cultural terms even as they improve their economic
status.