Certainly others have different reasons but I don't buy many (and often any) magazines these days because of my lifestyle.
I live in a rural community. The closest bookstore with a magazine rack is more than one hour away; the supermarket generally sells magazines I don't read except for Cooks, and I don't do much shopping at box stores.
The last time I had a Time, Newsweek, Life, New Yorker in my hand was in New Mexico. The last time I had an Atlantic Monthly, The New Republic or The Economist in my paws was last May in Pittsburgh at my daughter's house.
I alternate subscriptions and presently I am receiving three art magazines and the New York Review of Books. Last year I subscribed to Orion. I also subscribe to Poets & Writers.
When I lived in New York, I probably bought but didn't subscribe to as many as 12-20 magazines routinely. I'd walk into the neighbourhood B&N, underground kiosk or Amtrak station, browse the magazine shelves and come away with a much heavier bag.
I miss the magazines but not enough to subscribe to them. And I am already reading more news content than I care to admit (on line).
Will they vanish?