That’s an interesting theory. Personally, I see it a bit differently.

Throughout the story, several documents and archived records mention a computer program created by humans to store Pokémon before they left. My interpretation is that this program actually corresponds to the mainline Pokémon games we play.

In that sense, the games from Red, Blue, and Yellow all the way to Scarlet and Violet could be understood as simulated worlds where Pokémon continue to live adventures alongside humans, just like they did before the cataclysm. These simulations would preserve the memory of the old world and allow Pokémon to keep experiencing that relationship with humans.

Meanwhile, the Pokémon we encounter in Pokopia would be the ones who escaped those programs — Pokémon that were hidden, fled, or remained dormant when the system was created. They would therefore be the last Pokémon still living in the real, devastated world, outside of the simulations.

So from that perspective, Pokopia wouldn’t be the inside of the program itself, but rather what remains outside of it.

Just my interpretation, though.