Pokémon Red and Blue have only one slot for game data. One. In a game designed with choices that limit the possible Pokémon you can have in your team (a problem I will revisit later), you don't the option of saving the game file as a backup in case you make the wrong choice. Which do you want as a starting Pokémon? Bulbasaur? Charmander? Squirtle? Beyond their elemental types, you know literally nothing about them. I'm not saying you should get an entire move-list and evolutionary chart so you can make an informed decision, nor am I saying only having one game save file can doom a franchise's popularity, but it seems like a pretty basic thing to get wrong and the option of having one save file for each of the starter Pokémon has its advantages. Still, it looks like Pokémon won't introduce more save files in future games. Super Mario Land 2: Six Golden Coins has three save slots and that's a game where you have even fewer choices than Pokémon Red and Blue. Not to mention the basic fact that, with more save slots, other people can play your copy of the game. But if Pokémon is going to sell more cartridges I guess they wouldn't want that, would they?
I'm aware we have to suspend our belief here. It's a fantasy world and I'm not going to say that Super Mario Bros. has kids kicking turtles down streets, but the world of Pokémon is pretty brutal. From what I can make out, Pokémon and humans live in the world peacefully yet one of the main game objectives is to capture them and make them fight each other. Do we really want that in a game aimed primarily at kids? Okay, okay. Calm down. I haven't completely flown off the political correctness handle yet, I just want to point out that the game glosses over a pretty brutal and explicit aspect of itself. In fact, why is the in-game character a child to begin with? And why does a man who specifically describes himself as a 'Pokémon professor' need help from a small child to gather information on the subject he already knows? I'm not even going to start on what the games do with the whole concept of evolution, which is something I don't blame a lot of households not wanting their children being exposed to.