Mass media attention is a double edged sword. Fortunately, the paleo/primal movement is decentralized, and as such, difficult to attack or diffuse.
Previous dietary "fads", like the Atkins Diet, were centered around one individual (Robert Atkins), so personal attacks, inconsistencies, etc. could be used as fodder to discount his message (which, for the most part, was accurate).
While certain people have emerged as the Paleo vanguard (Cordain, Wolf, Sisson, DeVany), there are hundreds, if not thousands of independent thinkers, bloggers, scientists, etc. who are pushing paleo forward.
I think that the bottom line is that the SAD is self-defeating. People who eat (and live) according to it get sick, die early, and spend a lot of money in the process. SAD food production is also too dependent on fossil-fuel based inputs (oil, fertilizer, etc.) to persist much longer.
The hunter-gatherer lifestyle, however, worked, sustainably, for 90% of our evolution and it is likely that it is only a matter of time before we all return to our hunter-gatherer ways. Some of us are just getting a head start ;)