Maybe what he's trying to say is that right now, with the economy the way it is, there are a lot of people who won't dish out the money for a new 370Z, so you don't see many of them on the road. Give it a few years, and all the Zs people like us have will start to get traded in. As used cars, they will be much more affordable. Meanwhile, all things equal, there would still be the same number of people willing to pony up for a brand new Z in the future as there are now. Net result is more Zs on the road.
Having said all that, I fail to see the point of this observation. Yes, several years from now, there will be more 370Zs on the road. This will be true due to the simple fact that there will be more model years for the 370Z that have passed. So what? This is true for pretty much all cars. The 350Z was special, once upon a time. Now, not so much. It's just the natural order of things. You know, I'm sure when the PT Cruiser first came out, the morons who bought them felt special and exclusive for a while. Little did they know they would one day be called PT Losers.