Because having people download static map data for the entire planet just to play a game is untenable.
You shouldn’t have to download the entire planet though.
The game 100% should support installing local specific areas you wanna fly around, that anyone could then keep a copy of.
If a user wanted to cache an entire 8 TB of the entire world on a drive, they should be able to just do that (and thus have forever support without worrying about internet services staying online)
At least, as a snapshot of what the world looked like in 2024.
I don’t see why users shouldn’t have the option to locally HD save the data if they want to, to avoid maxing out their internet bandwidth in one sitting.