Goldman Sachs analyst Jason Armstrong said in a research note (via Businessweek) that Verizon iPhone sales may drop off. "iPhone sales will likely be a touch below the 2.2 million," his note said. This after meeting with investor relations executives from the carrier. This is likely as consumers decide to wait the extra few months for the iPhone 5, which has already been heavily-rumored and said to be ready for a September/October release.
We don't imagine this is unheard of as the usual mentality at this point is for people to just wait for the latest and the greatest. Another two or three months (at most) isn't a long time to hang onto your older handset.