While, I, too, have made known my disdain for the anime never letting Ash win a league, that is mostly because their official reason, "because then the series would be over", simply isn't true. Ash is always swapping out his older, more powerful Pokemon out for ones from the present generation, and gamers are constantly buying new Pokemon games after they beat the old ones, so there's no logical reason why, upon raising a team that won him the gold, he'd just call it quits, resolve his team was now too powerful for Pokemon battles to be challenging anymore, and never challenge another league with other Pokemon.
However, just because Ash could still logically go on challenging leagues if he won them, that doesn't mean it's what I want to see. For the near future, it would be nice to see the showrunners let him win another league--one that's actually in the video games, this time--but for the adult in me, a protagonist striving to be the best at a sport that doesn't even exist just isn't meaningful; even if he becomes more successful at it. Given the choice between Ash beginning to win leagues but continuing to frame his life around them, and Ash never winning leagues but moving on to more interesting conflicts, I'd probably choose the latter...
...the "probably" being there because I'm not sure what would constitute "more interesting conflicts" in this series. The world the Pokemon series inhabits has always been rather ridiculous, pretentious and shallow, and often when it gets into more weighty conflict it escalates to flat-out repulsive. I think I find new things to hate about the Yellow arc of Pokemon Special each time I think about what I hate about it. So I don't want Pokemon to stay mired in the doldrums of 2BA Master, but I also don't enjoy the quasi-Lovecraftian "end-of-the-world-as-we-know-it" scenarios that the series has increasingly normalized. I think I would prefer more character-centric conflicts and resolutions; good examples would be the relationship of Ruby and Sapphire in the manga, the episodes of the anime that show the Team Rocket trio in a more sympathetic light, and Brock's quest to meet a woman he clicks with. Some might argue that shifting the focus to these sorts of things would decrease the degree to which it's even Pokemon anymore, but then, when they're constantly teased by the series, why not resolve them and move on?