Oh, this thing. Thanks for asking this one OP, because I would love a good answer. WTF is the Resistance? And for that matter, WTF is the old Empire? I recently went to wookiepedia looking for details on the military structure of the Empire for reasons and found that Tarkin’s three main aides on the Death Star were two generals and an admiral (ground force and navy, respectively). I mean something as big as Empire’s could have branches of armed forces, I guess, but what were they all doing there? Maybe the Resistance has branches? Leia’s a general and that seems to be the highest rank…

But honestly, why does Star Wars even need ground forces as a separate branch? I know it’s canon, but it’s weird that would be any kind of ground force battles as we understand them. They have space ships capable of atmospheric flight too. How does any sufficiently large army fight on the ground without getting destruction rained down on them from above?