Because simple put it is owed to the customer on account of the facts that Skyrim had so many problems that it was almost rendered unplayable. The issues such as lag and bugs deglore are several times worse on the PS3. To make a long story short, we are owed a fuctional game. As I uderstanded it. It is a breeze for trained programmers to port to PS4... Further, Bethesda would make even more money off skyrim fans. As new bugs and glitchs would arise out of the new porting Bethesda would have to make patches. i would even pay for them to make it worth ther time only if the draw distance was incressed and other stuff... One would be a fool not to one please their fans and two make easy money out off it....