We cannot say with absolute certainty that Ash is even going to Alola, especially when, for all we know, they may just retire Ash simply because of XY's horrible ratings, bad movie sales, and poor merchandising sales (Anime may survive bad ratings, but there's little chance at survival if they also have bad merchandising sales and bad movie sales, and believe me, if one of their movies did so terribly it made even Pokémon Heroes look like a smash hit, you KNOW they did bad), and that's even assuming they're even going to actually HAVE an anime for Sun and Moon at all, instead of just cancelling the anime outright due to the reasons listed above (and it's not like a new game entry automatically guarantees a new anime series: DIC stopped doing Mario cartoons since Super Mario World, and besides, even the Pokémon Anime skipped over some games, like Pokémon Ranger or HGSS/ORAS.).
I'm not tired of Ash, but going by what you're saying with how badly XY tanked in regards to ratings, movie performance and merchandise sales, I would definitely be open to the Sun & Moon series being a complete reboot with brand new characters. If we had Brock replaced for BW, maybe we could have Ash finally replaced for this coming saga.
Cancelling the anime would be not good, considering the anime is meant to promote the games (and I mean the main series games that are introducing the new generation) and the only way the anime would get cancelled is if the games were stopped being made.
I wouldn't cancel the idea of Sun & Moon having an anime, it's just that the writers may have reacted to the bad performance XY had and decided massive change was needed, and that change is making a completely new reboot. Sun & Moon are already making huge leaps in how a main series Pokemon game is meant to be, such as fully proportional overworld sprites and the possibility of the PC going portable.