In a shareholders meeting Shigeru Miyamoto shared a story about Pokémon creator Satoshi Tajiri and one of the reasons Pokémon Red and Green came to be!
"A long time ago, Tajiri-san, the director of Pokémon, before creating the first Pokémon game, once joked to me ‘If you want to surpass Nintendo’s Mario, you can’t surpass it unless you sell 2 copies of the game to each customer.’
That is also one of the reasons Pokémon Red and Green were born. Like this, there are people who think ‘somehow let’s surpass it’."