If you go to a mainspace article that isn't considered a stub (for example, by clicking "random page"), click on the first link in the article that links to a Bulbapedia page, isn't in italics, and isn't in parentheses, and repeat the previous step, you will eventually find yourself at the Bulbapedia article about Canada. It's true.
Anyway, I’m sumwun. (obviously, because people other than sumwun aren't supposed to edit this) My first experience with Pokémon was from the TCG. My first card was this Seadra, which I found lying around in my house. I started playing the video games a few years later. So far, I played Emerald, Platinum, and SoulSilver. I don’t have time to breed for perfect IVs, so I battle on a simulator, specifically Pokémon Showdown!. I think it would be pointless to put in information about which formats I play, because that changes more often than I edit this page. As for Bulbapedia, it’s the best source of Pokémon information I’ve found so far. I tend to pay attention to detail, so most of my activity here consists of fixing unnoticeably tiny errors and adding random stuff to trivia sections.
Pokémon is a huge franchise, not only a TV show. If there was no Pokémon that can represent every branch, then the mascot should at least represent the core series games because that's where the franchise started. Pikachu doesn’t represent them very well, except for Pokémon Yellow Version. Pikachu only became important when the Pokémon anime started airing. The first episode was aired on April Fools day, so Pikachu’s status as mascot was probably just some kind of prank.
The mascot of Mario is Mario. The mascot of The Legend of Zelda is Link. The mascot of Kirby is Kirby. In case you don’t see a pattern, the mascots for all these games are one of their playable characters. However, Red is just a regular person, so it would make more sense for the mascot to be a Pokémon. The closest that a Pokémon could ever get to being a playable character would probably be the starter Pokémon, since they’re both titular and obtained at the beginning of each game. Thus, I think it would make sense if all three Kanto starters could be mascots. Of course, they’d have to be roughly balanced in terms of both usefulness and popularity.
If some Pokémon were to permanently be a mascot, it should represent some concept that's central to the franchise. Two concepts that have been significant in every branch of the franchise throughout the history of Pokémon are battling and evolution. No matter what you’re doing with Pokémon, whether you’re playing a core series game, a spinoff game, the Trading Card Game, watching the TV show, or reading one of the manga series, both battling and evolution are very important concepts. A good mascot to represent the first would be Magikarp. It’s one of the weakest Pokémon, but becomes better at battling through battling. A good mascot to represent the second would be Eevee, which is literally the evolution Pokémon.
Feel free to tell me that I’m wrong, but please explain why.