Yeah, I don't read magazines like I used to.  I don't watch TV like I used to, either.  Gosh, I used to listen to the radio to hear the Top Forty, too.  (That stopped about 30 years ago.) Don't miss any of it. But none of this is new.  Something (TV, I think) killed off the  large-format general interest "slicks"decades ago--Colliers, Saturday Evening Post, Look, and Life. THAT was the golden age! Canada's Saturday Night turned out the lights over 20 years ago. 

"Everyone’s mad for so-called long reads ..."  Surely you jest.  "Everyone" isn't and never have been, hence the half-century love affair with Reader's Digest and it's plethora of hard-covered "condensed books."  Why wade through 300 pages when you can get the gist in 100 pages?  

Having said that, many hard-copy magazines have stood the test of time: Redbook, Esquire, Cosmopolitan, Vanity Fair, Popular Mechanics, Good Housekeeping (despite the title!), Harpers Bazaar (despite the title!)  Lots more.  Frankly, I'm amazed!