I believe that Gary Paulsen is a well-remembered author because he wrote the book Hatchet and its sequels. That book is almost universally loved by younger students. In that book, Paulsen was able to find a lot of relatable common ground with his readers. He has a young protagonist that is under a tremendous amount of emotional turmoil from the very beginning of the book. His parents are no longer together, and many modern readers can relate to that on a personal level.
Paulsen then quickly brings Brian into immediate physical danger through a plane crash in the middle of nowhere. Putting Brian in this kind of survival situation is relatable because most readers have been camping at least once in their lives. Most of my students also admit to having been lost from their parents at one time or another. It might have been for only five minutes, but the experience is almost always traumatic. Paulsen takes that fear and pairs it with the knowledge of camping.
I think the other reason that Paulsen and his books are remembered so well is because he mixes real-world science into the narrative. Whenever I have to teach about light refraction and water, there is always a student that comments on Brian having to adjust for the light bend in order to spear the fish. Paulsen explained a physics concept in a way that makes realistic sense to a ten-year-old. That makes a deep impact on a reader.
Finally, I think Paulsen is remember by many readers because he is a prolific writer. He has written more than two hundred books.