^You had to make the covers look great for games of that era because you sure didnt want to have any of the games actual graphics there. Most of the Atari 2600 games had awesome art on the boxes and then well you know what was inside.
As far as the overall artistic trend, some are good some are bad and some are in the middle. Of course your going to try and copy a popular poster, thats how the game works.
So you're saying that they shouldn't do the great covers for games nowadays because the graphics are better, and yet a lot of games nowadays are just copycats of each other.