to answer your question:
it's not that runner's world is the cause, it is merely an affirmation of the "me-first, quick-fix" attitude of the distance running scene. don't confuse cause and effect; an effect of american general lack of effort has been the rise of a magazine that applauds that lack of effort and achievement.
rather than reward those who make years of sacrifices with a cover shot, they let some 5:20 marathon model, who walked it so she could claim she was a runner, run on a beach.
they then turn that around into the quick fix weight loss plan, using "runner's world" as the hook; because people see the exercise and the benefit, they think they will magically lose their beer belly just by reading the magazine.
and you're right, it IS "in spite of" gallowalking that US distance running is on the rise. the sport--sport is not taking walk-breaks so you can minimize sweat stains and pain--owes NOTHING to that sell-out.
i met the editors of runner's world in 1996 at the olympic trials where i was a recent HS graduate, looking for inspiration. those guys sat there and joked about how the hotels sucked (that they stayed in on the subscribers' dollar) and that they were going to "nap during the marathon." needless to say, i have not bought another magazine since.
you want running: go outside. that magazine is better of for wiping your ass, except that the glossy cover chick is non-absorbent.
greg