Not everyone they battle becomes rivals, Ash has battled a few people throughout the series and only Trip, Bianca, and Stephan ended up as his rivals, everyone else he battled was just one time. Same for Iris and Cilan who only have one rival each despite battling a few different people.
Originally Posted by waterpokemonrule
The only reason the writers would do that stuff before was because Ash and the others never really had rivals and as such they random nobodies filled that roll. But now they give the main characters rivals, they show training battles, and still show battles with random strangers.
I prefer the way it is now. I don't want to see Ash battle a bunch of nobodies, a few here and there is fine by me, but I enjoy rival battles, and more established characters who have an episode for themselves.
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