This might be kinda weird, but fun to think about. I hope I'm posting in the right place!

Was Cynthia always the Champion? She came and helped us a few times but didn't she leave the Elite 4 alone?

If she wasn't the champion, who was the champion before her?

She couldn't be the first champion because the Champion tradition has been going on forever right?

If thats right, why did they never say who the champion was in the previous games (even more on the 1st gen)!

I was just thinking about that...

I think it might be wise to ask why nobody calls you champion five minutes after you defeat Cynthia. Sure, you get the speech right after, but once the game resets, nobody cares anymore.

Yeah, in RSE, you'd be famous throughout the continent. In Sinnoh, no one gave a crap.

I think that Cynthia had always been the Champion for the story's purpose, although Frontier Brains might have preceded her.

In RBGY, Blue became the first ever Champion, which is what I'm assuming due to Lance and Blue's reactions.

In GSC, Lance becomes the Champion, but Red is the true Champion, of course. Lance is obviously a placeholder.

In RS, Steven was the Champion. In Emerald, Juan takes Wallace's place in his gym, so it could be assumed that Steven was beaten by Wallace and then went to better himself in Meteor Falls, a la Red. He's arguably a much tougher fight than before in RS, and definitely harder to beat than Wallace is as the Emerald Champ.

I think the champions are still free to wander around and whatnot, and aren't required to sit tight awaiting challengers at all times. Cynthia, for instance, says that she has a house in some region besides Sinnoh, although it isn't disclosed for security reasons. So I would say that Cynthia was indeed the champion for the entirety of the D/P storyline. Who preceded her is, of course, unknown.

Remember that Cynthia actually does follow you around throughout the game, notably atop Spear Pillar and in the Distortion World in Platinum.

we could also look towards the amine
she is a champion in the entirety of that as well so perhaps its the same in the games case.

If you want some reputation get 5 gold stars like me
(All legit Pokedex and proud)

Well if anyone listened at the end Prof. Rowan talks about he was in this room before. So I think he was the champion before Cynthia.

Hmm, I don't know. It makes sense for the professors to be previous champions. However, there could've been many champions in between them and the current ones, even changing every week or so.

I think there's some kind of distinction between champion as a rank and champion as a position. Since Red became champion in the first generation games, I suspect that he would still be champion on the G/S games, especially considering the level disparity between his and Lance's Pokémon. What I imagine to be the case is that there is always a 'residing' champion who spends time taking on comers at the League along with the Elite Four, as well as filling some sort of administrative capacity. Yet I don't see it in Red's personality to want to sit around and do that. So if Red was offered the position of residing champion at the League, he probably turned it down in favor of continuing his travels. So maybe he has the 'rank' of champion for winning? I don't know, and I don't think the anime has really touched on the subject in any detail.

As for Cynthia's wanderings, I think from Giovanni and Blue's absences in the first and second generations it's evident that official League trainers don't always have to sit tight.

Regarding the professors...

Well, every professor has seen their students inducted, haven't they? Oak saw Red being inducted after he kicked Blue's ass, Birch saw Brendan/May winning to Steven/Wallace, etc. As far as I know, Oak and Rowan are probably the only two that were actually Champions. Agatha (or whoever that old hag is) said Oak was a great Trainer before, and Rowan is apparently Oak's superior when it comes to Pokemon, so those two are probably the only two out of the four that have been in the Pokemon League challenge through and through.

Cynthia probably didn't beat Rowan to earn Champion status though. She probably fought a Frontier Brain or Lucian.

I'm so happy my question got this big!