Hopping is one thing, but the bit in the movie is specifically about having 32 full-sized screens going in a wall of TV sets.
My main point was about how we wrongly imagine the future as a linear progression of the present: in that one the writers clearly knew about fragmented attention but they extrapolated that as meaning future people would watch multiple TVs at once. This missed the boat, as fragmented attention is actually that you have a TV going in the background, you got a zillion tabs open in the browser of stuff you're going to "get to" any time soon, you hope, you have notifications popping from the 15 different messaging platforms that you limited yourself to and you have some games running on your phone.
EDIT: yeah and I forgot about audio attention there, thanks NG. You can have the TV running in the background, music playing on Spotify, while involved in multiple discussions via browser tabs, phone and email, while your playing a game on your PC and you've got several games on your phone for those few minutes you get up from the PC. Meanwhile you've got downloads and other background tasks your monitoring to make sure they're working ok.
Divided attention is actually more of a fractal / hierarchical thing, rather than a doing 7 things at once thing. The point about the movie being wrong is that their characterization of how information overload would work was wrong. Basically a lot of 80s media talking about the future had this theme of everyone turning into TV zombies: just extrapolating out the issues of that time, people being TV blobs and assuming the near-future was just more blobs. They failed completely to predict the 1990s phenomena where all the rubes got onto the internet.