Just exactly how do you know that? Just because that was the switch from iPhone 3G to 3GS?
We know because that's how Apple works. They are not coming out this year with the end all iphone. But if you really want to know how aggressive they are going to be in 2011, let's see how much better the iPad is. That will tell us all we need to know. If it's the best ever, with all the rumored specs than we can expect a brand new i5, if it's just a camera and speed/memory bump, than we are getting i4s