As I see things...
It's all about the quality of the presentation and the value of the content. And it always will be. And I think that, on both counts, most golf magazines fall short most of the time. That's a recipe for decline, if not extinction.
How many ranking lists and slice cures must one person read in a lifetime?
I'm a big fan of a couple of magazines: The New Yorker and The Week (both of which present valuable content, intelligently presented). Glad to hear Science News is worthwhile; I just started a test sub. for my daughter. I've heard innumerable people praise The Economist -- and would test that assessment, if I thought my life would improve by reading a magazine devoted to world politics and economics.
The problem for magazines, as for newspapers, will not necessarily be circulation; it will be advertising -- which, in fact, is fleeing to the Internet, where it is considerably less profitable to "the media" than it has been for the printed media.
Prepare to pay more for your print publications.