Lets just say that you are right and that they are running a 480 GTX. The 750ti actually consumes much less power, produces much less heat, is much more efficient, produces DirectX 12 graphics when they are released, and is much quieter. Besides, The 750 Ti FTW might be close to performance to a 480 GTX due to the high overclock.
A 750 ti performs at about the same level as a 660, which performs at almost the same level as a 480.
If the OP lives near a Microcenter, the 580 GTX still sells there for less than $150 and could even be a good buy.
As I saw the post, The person was only asking about a graphics card. Of course more RAM is better and I would agree with your sentiment that it would be a worthwhile recommendation.
I also agree with you that if they would replace the guts of the system, Of course one would recommend a higher graphics card than what suits their current system.
So, I guess all we can do is wait for more information then.