Let's assume that the evolution of mankind is not snuffed out by rampaging Pinsirs and Scythers hunting our evolutionary ancestors for over 300 million years. Let's assume that the year is 50,000 BC; it's still the Stone Age and civilization is still tribal. The first Kantonese settlers arrive in Pallet Town and begin to spread out; but are forced to face wild Pokemon.

Pokeballs most likely were not available to undeveloped Stone Age tribes. Yes, the Anime does depict a literal stone pokeball in the episode Claydol Big and Tall (AG104), but this was most likely magical (since the majority of other ancient devices that capture or control Pokemon used magic and this Stone Pokeball was created by a 'White Sage'). The oldest legit Pokeballs within the Anime are between 40-300 years old; meaning that they most likely require industrial or modern technology to be made. Even if Stone Age pokeballs were possible; I will assume that this tribe of Kantonese just don't have the resources, knowledge or magic to make Pokeballs.

My first conclusion is that this tribe will just instantly die; good luck trying to use stone spears to kill a Rhydon, don't try to outrun a flying Charizard as it burns down everything. Keep in mind that a Blastoise is basically a modern day tank that can also swim; even if you dodge its hydropumps, you aren't harming that shell.

Then we have Gyarados, good lord. This literal sea monster has multiple Pokedex entries stating that it can destroy entire cities (both ancient and modern) and that it is one of the most rageful, violent Pokemon ever. And yet this Pokemon is actually my argument as to why humans can survive in the Pokemon World.

Domestication of animals is extremely difficult to do. Wikipedia recognizes less than 50 truly domesticated animals (List_of_domesticated_animals) and there are over 8 million confirmed animal species. Youtuber CGPGrey made a simple and easy video about Animal Domestication, but basically for feral animals to be domesticated: that feral animal need to either be social enough to develop connections with humans, or the feral animal must be both too slow and too weak to flee or fight back so that humans can cage it and selectively breed the animal to be more docile. Wolves were one of the first domesticated animals since the social structure of wolf packs made them friendly enough to interact with and eventually befriend humans; and a single wolf is still weak enough for it to be killed or scared away by a tribe of humans if it ever does lash out. Lions are social, but are too violent and powerful for domestication. Coyotes are similar to wolves, but lack the social structure to trust and befriend humans. Even though wolves seem perfect for becoming domesticated into dogs, it wasn't an instant transition: dog domestication was a long process that may have taken thousands of years.

Back to Gyarados; my argument relies on the tan tomboy Nurse Joy from the episode The Joy of Pokémon (092). In this episode; Nurse Joy befriends a giant Magikarp without using a Pokeball. Even when it evolves into a Gyarados, despite not being tamed by a Pokeball, and despite Gyarados being a rampaging kaiju; they are still BEST FRIENDS (this is the greatest Nurse Joy ever!).

If a feral Gyarados can be tamed without any magic or Pokeballs, then almost any Pokemon can be. We know that this is not an outlier; Meowth was also once feral before joining Jessie & James, and Ash never puts Pikachu in a Pokeball (Ash did need to drag Pikachu with a lasso in Episode 1, but they are now BEST FRIENDS). There are plenty of other examples; officially called "Walking Pokemon". The Kantonese tribes will guarantee their safety and conquest of the region by becoming Pokemon Trainers; bypassing the pokeball for a more realistic method of taming. Ironically; Gyarados might be one of the easiest Pokemon to tame due to how easy it is to capture and contain Magikarps; an artificial pond or aquarium is all you need to keep them from escaping, and thus giving the Pokemon Trainers plenty of time to form a friendly bond.

Now that we know that Stone Age man would need to be Pokemon Trainers as well, then we must see how Pokemon would change the development of mankind.

The ease of taming means mankind would use Pokemon as farm animals tens of thousands of years before the normal animals would be domesticated. Arcanine would replace dogs, Rapidash would replace the horse, ect… Since normal animals are harder to domesticate; they would be mostly replaced by Pokemon. The only scenario where this might not be the case is if Pokemon used as meat livestock retaliate; forcing humans to use the safer cattle instead of Tauros (some of whom can use hyper-beam and earthquake: not safe at all).

But the Field Moves will make significant impacts on even the smallest and simplest tribes. Want to construct buildings? Use Strength and Rock Smash if it's stone, Cut if you want a log cabin. Having issues with invading armies? Use Dig to make underground tunnels and homes. Injured? Use Soft-Boiled to heal you in an instant. Want to discover America? Use Surf to find it, and Fly to travel back and forth.

Pokemon are able to travel across various terrains and biomes with no issue, which allows travel and trade to be on par with the transit systems of the 20th century; with the only downside being speed and cargo carrying capacity. The Sub-Saharan African nations will have more direct contact with Eurasia, the Americans will not have immune systems oblivious to Old World diseases and might better resist European conquests, and the concept of globalization might be established before the Bronze Age. All of human history can be drastically shifted by the communication that domesticated Pokemon can provide.

Electrical Pokemon have the potential in introducing electronics. Electrical power has been experimented with for millenniums before the 1700s, but such primitive batteries could not capture, utilize nor maintain electricity. Yet there are multiple episodes within Pokemon that confirms that Electric Pokemon can use their electric moves and abilities to charge modern electronics; Pokemon are batteries. With this; early man can experiment with Electric Pokemon and potentially make early electronics. Even if we assume that electronics don't get invented until 1500 AD: that's still centuries of technological advancements that would advance human technology significantly further than in our timeline.

Now while there are some Pokemon like Machamp and Hitmonchan that are humanoid, they don't appear to have the same human mentality that would make them develop into a society or civilization; yes they are smart enough to communicate, but they still act like animals otherwise. They don't appear to be intelligent enough to be anything but Pokemon. Yet there are multiple Psychic Pokemon that are not only smart but absurd geniuses.

Alakazam alone would be the greatest asset for a young human civilization. His IQ is 5000 at least, with his brain cells constantly growing to increase his intelligence and memory indefinitely. Even if we ignore his Pokedex entry; Alakazam's massive head and his Psychic powers confirm that his brain is far larger than a human's brain. A civilization that is able to use Alakazams as scientists would manage to create a utopia overnight; Alakazam would be able to not only discover multiple technologies but could also create philosophies and political systems far more advanced than what we dumb humans can comprehend. Even if Alakazam somehow went extinct; there are other Pokemon with superhuman intelligence that would fit this role. This is still making many assumptions however; it is still quite possible that Alakazam's intelligence is designed primarily for his psychic abilities rather than understanding and implementing human progress. So for the remainder of this analysis: I will look at the Pokemon World as depicted in the canon rather than the 'Alakazam Utopia'.