If the horses are so used to running, why take them out of the Kentucky Derby or the Preakness? Seems to me some owners are more interested in being the “spoiler” than anything else. That takes a lot of the joy out of watching, especially for casual fans (comes across more like, as Rush Limbaugh says, phony, plastic banana, good time rock and roll).
I dunno.... you got a horse that you don’t think can win all 3 so you don’t enter all three. The guy won a lot of money today when he won Belmont. That’s a good reason to work a good strategy. California Chrome hasn’t figured out that not all of horse racing is about him.
To run in other races. To make money. The owners are interested in making money. Race horses are an investment, they get a winning career then get bred. What would be phony is to limit the Preakness to only Derby runner and the Belmont to only runners of the previous two. That would be a deliberate construct to try to create a Crown winner. Each race has their rules for entry largely independent of each other, a Crown winner has to beat them all.