Think about pretty much every successfull car that has ever been produced.they gain a fanbase and a reputation and then cancel them.only to revive and reinvent them a few years later.just to sell more and make a scene.
its good for sales and marketing.they wont be bringing back two cars at once cuz i believe you can make more money by having revived cars come back one at a time.
think about it this way,once the new gtr gets old and every ricer and his grandma has one then they will come out with something else to make everyone cream there pants about in anticipation.aka silvia.
just my two cents..
cheers!