Perhaps the following is an oversimplification, but I think we can
generally characterize the two camps. Those with documents that are a
"push" to the customer, such as advertisers, tend to want the control that
technology Adobe Acrobat offers. On the other hand, those whose documents
are more intended to inform, where it's more of a "pull" model (the
customer wants the info) are more inclined to choose structured text.
On the Internet today, "push" is generally considered a bad thing. At some
level, net users usually don't like to get stuff that they didn't ask for,
explicitly or implicitly. I think that's why structured text has been the
focus so far. But as advertisers start to carry some of the costs,
publishers are going to want their usual level of control over the
appearance, and hence (in theory) the impressions that they make.