Yes but not as much as they would be if they were exclusive and zero if they just ended up on the old systems :P. Some people who are interested in the new console will buy if cross-gen games exists. Why would they want to get the lesser version when there is the best version on a new console they are trying to decide to buy? It also stacks up the list of games available on the new system, another good reason to buy. Kind of similar to having backwards compatibility. If the new console can play the old games than you can sell the old one and buy the new one. Obviously this is a much smaller scale concept but if games like Beyond Two Souls and the Last of Us became cross gen then you'd probably see a lot of the core opting earlier for the PS4 than they might have otherwise.
Before the PS3 everyone was nice to me :(
