I can't answer all of this questions, but "why not offer 2 versions and allow the user to choose" was mentioned here [0].
Helldivers 2 is a multiplayer game, for the game 2 start, everyone in the lobby needs the game to be fully loaded. If one person would choose to have a slower version, it would make everyone wait longer. Which is definitely not a trade off you are willing to make as a game developer because makes the experience for other players worse.
There could be other options and better optimizations, such as lower textures that you mentioned, but I agree with the developers on having only a "fast version".
Helldivers 2 is a multiplayer game, for the game 2 start, everyone in the lobby needs the game to be fully loaded. If one person would choose to have a slower version, it would make everyone wait longer. Which is definitely not a trade off you are willing to make as a game developer because makes the experience for other players worse.
There could be other options and better optimizations, such as lower textures that you mentioned, but I agree with the developers on having only a "fast version".
[0] https://www.pcgamer.com/games/action/helldivers-2-dev-explai...