I agree with the lack of a tutorial, but about everything else, did you actually beat the game? A lot of this is addressed the further you go.
For instance, take the choice of whether to build an auto-harvester for an ore node with 29 ore in it. Since the extractor costs 25, this deeply cuts into the player's income.
Don't build extractors for any deposits <40, or maybe <50, ore. If you want to go for 100% clean planets with no losses, you eventually must rely on extractors, especially for deposits >80.
I have thus far not encountered a time where it felt like building a turret or harvester was the correct choice, which is sad, because they seem like such an interesting part of the game.
I think you definitely have not beaten the game yet. If you can leave every planet without turrets with zero losses + 0 deposits left, you're unbelievably good or got insanely far den spawns.