Like the others said, it's probably to test the prices and to see if anyone is willing to pay for that price. For example, If you haven't notice, the the 4 hours option is gone. Sony must have notice the negative feedback, so they are slowly trying to figure out what prices would consumers be more comfortable with.
I think I wouldn't mind a 3-Day option for $3-$7 (depending on how old or new the game is) it would be great for a weekend rental.









