Instead of being cooped up in the train, staring at each other all day, which is very much what happens to CI teachers who are following lesson plans in their classrooms, when we do targetless CI we are free to run around the boat, playing hide and seek, skipping the quizzes, playing hooky, having fun.
On ocean liners with names like Spirit of the Sea, Dauntless and The Intrepid we can run around the deck because on those boats the promenade is like an indoor track that we can actually literally run around on it, greatly expanding instead of shrinking the possibilities that can happen in our classrooms. There is much more to explore and do on an ocean liner than on a train.
My favorite place on those big ocean liners/targetless stories is the dining hall, where the food seems limitless and wonderful and tasty and we all get to sit around at a big table with people who are interesting and fun and talk about things in an unguided and natural way, as per:
https://benslavic.com/blog/lart-de-la-conversation-and-tprs/
To me, the essence of TPRS and the essence of what Ray and Krashen have give us is right there, in that article.
Susan Gross is one of the early TPRS trainers who started codifying TPRS, and when Step 1 appeared, things started to get difficult and congested, and everybody left the Harbor of Big Ships and crowded onto the busy little CI trains, and the clackety clack of the train on the tracks became the norm, and only now are we returning to TPRS as it was first conceived. Only now are returning to the sea.