To back this all up, just look at the history of humanity transporting plants and animals all over the place and fucking shit up, all because we figured out the absolute best defense against our own predators, being too fucking smart for our own good.
You’re assuming this is the norm rather than something being transported and not able to survive in the new environment. Kudzu, as an example, is an invasive plant from Japan that has taken over the Southern US due to lack of insects and animals that eat it. But if Kudzu was brought to the Amazon instead, it likely wouldn’t survive due to the high acidity of the soil. The plants there are specialized and it’s unlikely for a plant without this specialization being able to widely spread.
You’re assuming this is the norm rather than something being transported and not able to survive in the new environment. Kudzu, as an example, is an invasive plant from Japan that has taken over the Southern US due to lack of insects and animals that eat it. But if Kudzu was brought to the Amazon instead, it likely wouldn’t survive due to the high acidity of the soil. The plants there are specialized and it’s unlikely for a plant without this specialization being able to widely spread.