system
Given the following post, respond as if you're commenting on Reddit:
human
[Starship Troopers] Why doesn’t the Federation use tanks (and other vehicles) against the Arachnids?


Outside of mechs like the Marauder, the Federation doesn’t seem to use any ground vehicles at all when fighting the Bugs. While this makes sense in planets like Klendathu which is full of irregular terrain and caves, we never see the the Mobile Infantry use any land vehicles like tanks or APCs even in regions suitable for their use. 

Even if tanks aren’t effective in direct combat, wouldn’t it be worth it to use APCs for fast transport or missiles trucks for artillery instead of relying exclusively on bombers and orbital barrages?
gpt
In the films it's different than the book. The books the mobile infantry are essentially walking tanks and armored cavalry and scout vehicles depending on there role.

In the films there's no real mechanized military forces as the drop ships and space craft have made them redundant. For centuries the Federation has fought with ground troops and air superiority and orbital attacks. Tanks and artillery are relics of war fighting that haven't been on a battlefield in generations.  This logical gap for military strategy has been slowly addressed by the Federation following it's disastrous opening campaigns of the first interstellar war. The Sky Marshals are distracted by political matters but they're still making progress and with the successes of the marauder suit and later exo-suits we're beginning to see wide spread adoption of mech units and doctrine focused on small scale precision forces rather than massed mobilization.