The news magazines have always had a "relevant niche".....in-depth analysis. I used to read all three back before they became liberal propaganda organs. Time went first, then Newseek. USN&WR held out the longest before succumbing to the socialist propaganda disease, but it "went bad" as well. Once people realized that they were not getting un-biased news, circulation dropped, and has continued to drop. Nowadays, I can get more honest (if not in as much depth) news analysis online. Good riddance.
Libraries (in schools and public libraries) and waiting rooms probably account for a significant portion of market share.
If CNN wasn’t forced on viewers in doctor’s offices and airports it’s ratings would probably be on par with MSNBC.