[Theory] Pokemon, Digimon and Yu-Gi-Oh share the same universe?

[twillight]

In the pokemon-franchise we see a world filled with pokemons captured and trained by humans. These pokemons are transported and stored in digitalised form.
But the process does not stop here. Humans also invented entirely digital pokemons like Porygon as the next step (see Cyber Soldier Porygon). For more that "digiworld" exist in Pokemon check "Exploud and Clear" too, which even has a fight like the first segment of Digimon - The Movie.
For the third step they created Mirage Technology, what is like a holodeck in Star Trek, create solid holograms as long as they remain in the Mirage Field (The Mastermind of Mirage Pokémon). The created pokemons can absorb data to grow in size and power too, and a worldwide distribution-system is also developed. As we even see a Porygon in the Real World (outside the Matrix), this is even more confirmed.
The technology likely got advanced with Deoxyn get loose (check his multiplying ability). We also see artificial talking modular pokemons in Destiny Deoxin too (those security robots).

While the technology got rejected initially, it is entirely possible that by time other researchers made the technology fit to the "pokemons are individuals" concept - and create digimons.

First, the government tried to cover the digi-world (Data Squad), but it slipped out, reaching everyone, including children, who still used an undeveloped technology, and instead of digi-evolution they still only merged digital pokemons, like Mewtwo in MoMP (Xros Wars/Fusion).
Eventually the technolgy got perfected, and instead of mashing data, real digi-evolution is created (Digimon Tamers).
But that still wasn't the end of it. Getting access to the advancement humans realised they don't need a separate entity, and can merge with the mirages themselves, becoming superheroes and supervillains, to the point where literal equialents of gods were created (Digimon Frontier). The merging-technology still existed too as a back-up solution likely (creating Susanoomon at the end of the season).
Of course "animal" life got practically extinct at this point, and what remained lost its sentience (are there animals in either Digimon or Yu-gi-oh?).

But trusting god-like powers to humans is dangerous as we all know. This led to the destruction of the world, preserved in legends of Yu-gi-oh.
The whole dueling-system as result ended up restricted into serious limitations: duel in an arena, computer-governed to avoid cheating, no intelligence allowed to the creations.
Ok, the truth got corrupted, speaking about "magicans" and "summoning creatures", but the core remained, as well as their basic of society: monster-battles.

 

[RoreyG]

Animals do exist in Digimon (Tai and Kari have a pet cat) and Yu-Gi-Oh! (Rebecca Hawkins, one of Yugi's friends, has a horse that she rides).

I see the logic in linking Pokemon and Digimon. However, I think it would go that normal animals were uploaded into the Digital World and this changed their DNA so that when they came back out, we would have the first prototype Pokemon.

The Yu-Gi-Oh! link is a bit of stretch. It's specifically stated that all of the events of Yu-Gi-Oh! started in ancient Egypt during the time of the Pharaohs and both evil and benign spirits were used to battle (demons and spirits, not animals). Pegasus, having discovered the game though his archeological expeditions, decided to revive these "shadow games" in the form of a trading card game and created the rules (cause you can't have a game without basic rules). As the series progressed, Kaiba created new technologies which enhanced the playing experience (thus the holograms). I fail to see really any link to Yu-Gi-Oh! from Pokemon/Digimon. Its nature and origins are fundamentally different from those two.

 

[Gligar]

Animals do exist in Digimon (Tai and Kari have a pet cat) and Yu-Gi-Oh! (Rebecca Hawkins, one of Yugi's friends, has a horse that she rides).

I see the logic in linking Pokemon and Digimon. However, I think it would go that normal animals were uploaded into the Digital World and this changed their DNA so that when they came back out, we would have the first prototype Pokemon.

The Yu-Gi-Oh! link is a bit of stretch. It's specifically stated that all of the events of Yu-Gi-Oh! started in ancient Egypt during the time of the Pharaohs and both evil and benign spirits were used to battle (demons and spirits, not animals). Pegasus, having discovered the game though his archeological expeditions, decided to revive these "shadow games" in the form of a trading card game and created the rules (cause you can't have a game without basic rules). As the series progressed, Kaiba created new technologies which enhanced the playing experience (thus the holograms). I fail to see really any link to Yu-Gi-Oh! from Pokemon/Digimon. Its nature and origins are fundamentally different from those two.

I rather fail to see a link a strong link between Digimon and Pokemon. Yu-Gi-Oh! can link to pokemon imo.

 

[twillight]

It's specifically stated that all of the events of Yu-Gi-Oh! started in ancient Egypt during the time of the Pharaohs and both evil and benign spirits were used to battle (demons and spirits, not animals). Pegasus, having discovered the game though his archeological expeditions, decided to revive these "shadow games" in the form of a trading card game and created the rules (cause you can't have a game without basic rules). As the series progressed, Kaiba created new technologies which enhanced the playing experience (thus the holograms). I fail to see really any link to Yu-Gi-Oh! from Pokemon/Digimon. Its nature and origins are fundamentally different from those two.

The fact they found their artifacts from "Egypt" just means they did not find stuff elsewhere YET.

More importantly take notice the mirage-technology, and the humans merging with/into digimon feature. Those merged beings are what could be called battle-spirits: demons if villains like Team Rocket/Palsma/Magma etc., and spirits/angels if they are Pokemon G-men, or simply such trainers like Ash&Co.
The Shadow Games are nothing else but degenerated tales of pokemon/digimon battles.

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NEW INFO:
Maybe "Egypt" is not "Egypt".
If you check the episode of pokemon where Ash first meets the Pyramid King, the tomb has "egyptian" hyeroglyphs on the walls.
And the possession-effect is the very same on Ash and the yugioh-guy.