War in Sci-Fi Movies

Seeing these photos and watching the trailer for Battle: Lost Angeles again,

The Hollywood depiction of war, especially in science-fiction movies, is very "linear," 1GW. It looks good on the screen maybe, but it's not "realistic." The most blatant example would be the Star Wars prequel trilogy, but other movies include Steven Spielberg's War of the Worlds, Independence Day, and Avatar. It's just a confrontation between two forces. It may be easier to portray war in this way to the audience. A force using a lot of maneuvering and bypassing the enemy would seem boring, in comparison, even if it is better warmaking.
(Even showing a realistic flanking maneuver in the 20th century might be difficult?)

In these movies it is presumed that a superior army would confront the weaker army head-on, especially if they are virtually invulnerable (force fields, better armor, etc.). Then with its superior firepower (energy weapons, ballistics) it would just annihilate the weaker force (usually the humans). This it would do instead of using its advantages in conjunction with exploiting the (other) weaknesses of the enemy. It is convenient for the plot that the aliens usually seek to eradicate all human life anyways, so they do not need to demoralize the enemy to induce a surrender. If they're going to wipe out all mankind, they might as well do it when the opportunity presents itself.

On the flip-side of this -- the humans never attempt sophisticated counters to the technologically superior aliens. (Who may not have superior numbers.) Instead of using guerilla tactics and such, they always charge at the enemy, usually in the open. I would hate to think that this is what the US military would do if we were actually confronted by an alien military force.

An exceptions to this might be District 9, when the PMC's security force tries to take out the alien power suit, but the mercenaries learn how to disable it at a terrible cost. (It is similar to the opening scene of Patlabor 2, when the guerillas hide themselves in the jungle and do not confront the UN military labors in the opening, drawing them into the jungle and then using RPGs and such to destroy the labors.)