Flawed assumption. We have 2 to 3 daily polls on the popular vote being done daily. State polls are far less frequent and more difficult to do. The electoral maps are based on the most current state by state data. The state by state data can lag by weeks.
The daily polls are indicating that the electoral vote map is about to change toward Romney.
Interesting comments regarding state versus national polls.
Looking at the Rasmussen polls for today on RCP shows the following:
Missouri
Romney +11
McKaskill +8
Missouri going GOP for President and Democrat for Senator. I know several things can influence that type swing but I still find it interesting.