I think I can offer some possible answers to your question.
Why? Because magazines, in many cases (as stated here) are more convenient. It's a bit harder to curl up with your laptop.
People still like to hold a magazine, look at the big pictures (a computer screen isn't quite the same). A well designed magazine is just more beautiful than most web sites. They like to feel the paper of a high quality magazine.
They like to be able to throw it in a bag and read it on the train instead of lugging and unpacking a laptop and using their battery power. You probably wouldn't take your laptop to the beach.
It takes time to prepare your digital files to read when you're not going to have internet access. It's easier just to bring a print mag.
I can think of some other reasons. Most websites are pretty clueless about ads. When I get a paper magazine I value the ads. Most websites including this one make ads annoying! I don't want them flashing or sitting in the middle of the text. When they do out comes adblocker.
Second is that most web desginers seem to hate users. Take this site for example. Why is only 1/3 of the screen being used? I understand the use of white space but I want text! I don't want or need huge cream colored bars on the sides of my text to make it easy to read. It is like reading through a pin hole.
Third is frankly lack of depth. Motorcycle.com does good articles but because I can come every day I want new content every day. That makes life very hard for them. I want to see more bike, helmet, and equipment reviews and comparisons. The paper magazines seem to get all the good toys first. Probably because they have more readers which is a shame.
I would really like to re-subscribe to motorcycle.com but the new website I feel is actually a lot less useful than the old.