Will some Pokémon species be retired from the Pokémon franchise for various reasons?

Transfer-only? The Pokemon that have been unobtainable due to Dexit are incapable of being transfered to those games at all unless they're coded into said game's Pokedex. One would require god-level expertise in figurative techno-wizardry (and at least a small bit of literal techno-wizardry) to code even one of them into a game where it's normally unobtainable.

Your hilarious hyperbole regarding the difficulty of implementing missing Pokémon aside...

So you agree with me? There are Pokémon that have been retired and can only be obtained in Home by transferring them from earlier generations.

there was an episode that only aired in Japan that cause ceizures to many of the people who watched that episode kind of stopping any future appearances of porygon and its evolution in the anime

Nah I don't think so they will do that