The question doesn't need to be tough. Look at it from a King collector's perspective and just imagine how much different everyone's collections (on here at least) would be different if the first published book determined the ENTIRETY of a publisher's customer base. How many 'Salem's Lot (Centipede) owners own previous books Jared did? Or on a bigger scale, think about all the King books Cemetery Dance published and think how many collections would be different if people had to have bought CD #1? Or not being able to get The Green Mile from Subterranean? Or not being able to get a Ray Bradbury or a Neil Gaiman book because you missed some crummy Kelley Armstrong book (or a Connie Willis novella - this one's for you ur2ndbiggest fan).
Appeasing the customers who got in on the action with The Eyes of the Dragon portfolio would be neat - in theory. Things would get messy if those owners started passing on future books. Would they still hold the rights to that number in 2030 even if they bought nothing since 2018?
Just food for thought without any prior knowledge as to what the next book might be.