>>53818456He did the thing that fans chastise each other for when they do it in game, use legends and mythicals. Ash was pretty good in DP, he had a solid team and beat his rival, which was satisfying because Paul was a prick. When he beat the rival character, the studio clearly thought his arc for the series was complete and created Tobias as a means of forcing Ash to lose while not diminishing his ability, so he had a reason to continue to Unova. BW then diminished Ash's ability and overall character independent of Tobias, so in the end, Tobias didn't need to exist.