If they replaced Ash earlier, would another character not have sold as well or been as popular with children?

[Kathylikestoread]

I don't think so. The traveling companions get replaced every season, and they still have some popularity. May and Dawn are both very popular characters. And I think that the chances of people dropping or disliking the show is very rare.

 

[Nicolas721]

I think the executives probably didn't care or liked Ash that much in the sense that they saw him just as "the generic protagonist" who can carry the anime forever. The anime didn't went on because of Ash, Ash went on because of the anime, and he was cool enough generations of children could like him forever as long as he kept catching Pokemon and being the embodiment of the franchise. But eventually there was a point of change of mentality, and I think it came with the backlash to the Kalos League results.

I think that was the point that the writers realized that the anime still had an older fandom that was more than willing to go angry and tarnish the franchise's image if the protagonist they had been following for decades wasn't allowed to escape his fate as an static character. Sun & Moon was already in production so he was going nowhere, though the backlash obviously impacted the end of that series, and Journeys was his big goodbye though not as obvious as it could have been so new viewers would still relate to him.

So, did the writers had those kind of questions? Probably, but I think those discussions didn't got too far until they saw what Ash really meant to the public. They likely saw Ash as interchangeable for any game protagonist.

 

[Kathylikestoread]

I personally think that another character could do the same thing. They could make a new character, and generations of children could still relate to them. I personally think that they should switch protagonists for every season, just like the manga, Adventures does with every arc.

 

[Daren]

It's always difficult to discuss paths untaken, but in all honesty I don't think Ash was the big selling point of the show; it was being Pokémon. More central characters have been phased out before. Admitedly, the longer the show ran with him the riskier it may have felt but from what I can find online, Horizons ratings have dropped from JN but not in a particularly unusual way (each series has done worse than the last one).

The fanbase would have had a whole different set of flame wars debates at the end of each region.

 

[Twilight-Kun]

Given the treatment of Ash by the end of the series, replacing him after Kanto probably would've been a good move

Ash wouldn't have titles like The Johto Jobber and The Shame of Sinnoh

Heck, they may have remembered Galar exists instead of spending so much time literally anywhere else during PM19 if they'd been using Galar characters

 

[Die-Hard Dragon Devotee]

I don't think Ash was the big selling point of the show; it was being Pokémon.

Exactly. I mean......most people aren't watching the Pokémon for the human characters. They're an important part, yes, but......most people (myself included,) are mainly watching the anime to see the Pokémon themselves, the eponymous characters of the franchise, on the "big screen" so to speak, I think.

More central characters have been phased out before.

Brock.

Admitedly, the longer the show ran with him the riskier it may have felt

That's Yuyama/the higher up's fault for utterly refusing to let him go.

but from what I can find online, Horizons ratings have dropped from JN

While I can understand why that is (Ash leaving,) I also find that a tad ironic, since I consider Horizons to be better than Journeys.

but not in a particularly unusual way (each series has done worse than the last one).

Exactly. It wasn't Ash continued presence alone over the course of the anime's run that has caused its problems in recent years. If you ask me, the very core of the Pokemon anime itself is in a state of decay.