Yeah I feel like they'll always leave it open to a DB situation where they say f it and bring Ash and Pikachu back if things go southThere's always a way back. If this series really ends up flopping (which it won't), they could easily return to Ash IF his story is left open-ended. If they actually give it a proper conclusion, hell even age him up a bit (or a lot, in case the new mc is his daughter), they could always rely on AUs or make a series based on pre-timeskip Ash.