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He won't. Kalos was when he finally realized he's not meant to be a champion.
The true elite, like Alain, take the title on their first or second try. They're either good enough the first time around, or they realize why they lost and don't lose again. When Ash lost in Johto too, he truly failed and his mediocre fate was sealed.
Gary understood his limit as a trainer and went into a field he could actually excel in, but Ash continued to flail about until he finally broke from the strain of trying to do something he can't.