Does anyone realize something about every Nationwide race?

Does anyone realize that when your watching a Nationwide race the same drivers are always in the top 5? It's basically always Kyle Busch, Brad K, Carl Edwards, Kevin Harvick, and Joey Logano. I bet anything that by Homestead these guys will be the only ones with the wins and maybe some other cup drivers. The Nationwide series is pretty much just an easy practice for the cups drivers for the cup race the next day.