I agree on all points! Players should be able to do whatever they want.
However, not in the context of newbie players. To stay within your EVE example: Imagine an total EVE noob, starting out at JITA and trying to thrive there. It wouldn’t work, you even said it yourself, that this is a harsh environment.
Eventually we want players to build their own Comex and they can enforce whatever rules they want, they can trade whatever they want and there certainly won’t be any MMs. I would be the first to applaud when they manage to build a PrUn version of Jita. But: Player-built Comex are not a thing yet, and we have to provide means to trade in the meantime and we also have to care about the newbies or else the universe will be empty. That is the very reason for the restrictions of the starter planets.
Besides, there are local markets! If you want to break free from the starting planets feel free to move to a non-faction system.
We won’t do that, because if every starting planet has the same specs the game is boring. We want the factions to feel different and unique. If a specific starting planet does not suite you, there is always the option to COLIQ and chose another one.