There’s a pretty strong pattern here to the subscription offers we see.
They’re usually done by publishers. (Safari isn’t a publisher anymore, but it was started by publishers.) That means they’re working with the publishers’ margins (bigger than an aggregator’s margins). Controlling the product flow means they can make good use of intereaction with their audience, learning through data and conversation what they should be doing next. And, most important of all: from a product offer point-of-view, they’re focused.
They’re precisely the opposite of Spotify or Netflix or Audible who all want every single song, movie or TV show, or audiobook they can lay their hands on.